Fosforilirani receptor HER-2 kao pokazatelj rezistencije karcinoma dojke na terapiju trastuzumabom [Phosphorylated HER-2 receptor as an indicator of breast cancer resistance to trastuzumab]

About 20-25% of breast cancers have over-expressed HER2 receptor, leading to aggressive behavior of cancer and poor disease course. Implementing anti-HER2 therapy with trastuzumab improved disease outcome and survival of patients. Yet, a significant number of patients do not respond to therapy. HER1, HER2, HER3 and HER4 receptors belong to the epidermal growth factor receptors family. Bonding of growth factor to the receptor activates dimerization of HER receptors, resulting in phosphorylation on cytoplasmic domain and activating the signaling pathway. Our study was performed on 124 samples of HER2 positive breast cancer with the assumption that HER2 phosphorylation is a true marker of receptor's activity and that HER2 dimerization with other HER receptors contributes to the acquisition of trastuzumab resistance. We performed immunohistochemical staining using specific primary antibodies against phosphorylated HER2, HER1, HER3 and HER4, and investigated the correlation between their expression and correlation with the resistance. Our results found that HER2 receptor is predominantly phosphorylated (66.2% pHER2+) and positive pHER2 status is a marker of a good response to trastuzumab (P <0.001). Negative phosphorylated status of HER2 is significant in the HER2 intrinsic group where 33.3% of the patients had a disease recurrence. HER1, HER3 and HER4 receptors were expressed in 9.7%, 70.2% and 71% of HER2 positive carcinomas, retrospectively. Coexpression of pHER2 and HER3 showed a statistically significant correlation (P=0.013). Patients with negative pHER2 and positive HER3 or HER4 had poor survival, and resistance was recorded in 35.3% of pHER2‒ /HER3+/HER4+. We can conclude that the positive phosphorylation status of HER2 determines patients who will benefit from trastuzumab therapy. Negative status of pHER2 refers to patients who should undergo dual therapy in first line treatment, especially in the HER2 intrinsic breast cancer group

Mutacije kod melanoma u progresiji

In this review, we present the findings from the literature on several new molecules that can be targeted in the melanoma treatment process, especially metastatic melanoma, since five-year survival rates are below 20%. Recently, melanoma has been defined by mutations that occur in oncogenes and lead to melanomagenesis. A mutation in BRAF gene selects the patients for targeting therapy with BRAF inhibitors. Although BRAF inhibitor therapy is associated with clinical benefit, the majority of patients with the BRAFV600-mutated metastatic melanoma develop resistance, usually within the first year. Clinically significant discrepancy in BRAF status, between primary melanoma and its metastasis were detected in about 15% of cases. There are no specific recommendations on BRAF re-testing, but might be clinically relevant to repeat testing on recent metastatic sites in cases of previous BRAF wild type results.U ovom preglednom radu, predstavljena su saznanja iz literature o nekoliko novih molekula na koje može biti usmjeren razvoj ciljane terapije u procesu liječenja melanoma, osobito metastatskog, gdje je petogodišnje preživljenje manje od 20%. Melanomi su sve češće definirani mutacijama u onkogenima koje dovode do maligne trasnformacije. Mutacije BRAF gena određuju bolesnike za ciljanu terapiju BRAF inhibitorima. Iako bolesnici imaju kliničku korist od terapije, većina bolesnika s BRAFV600 mutiranim metastatskim melanomom postanu rezistentni unutar godinu dana. Klinički značajne razlike u BRAF statusu između primarnog melanoma i metastaza, javljaju se u oko 15% slučajeva. Nema specifičnih preporuka za ponovno BRAF testiranje, ali može biti klinički značajno ponoviti testiranje na novonastalim metastazama, u slučajevima prethodnih BRAF rezultata divljeg tipa

Istraživanje genotoksičnih učinaka irinotekana na ljudskim limfocitima periferne krvi primjenom različitih biomarkera u uvjetima in vitro

In the present study a multi-biomarker approach was used to evaluate genotoxic effects of irinotecan administered in vitro in its therapeutic dose (350 mg/m2) on non-target cells, peripheral blood lymphocytes. The levels of primary DNA damage in lymphocyte genome and the dynamics of its removal were assessed using the alkaline and neutral comet assay. Lymphocyte viability and the induction of apoptosis following exposure to irinotecan were studied by simultaneous use of a fluorescent assay with ethidium bromide and acridine orange. The levels of residual DNA damage were assessed by SCE assay, while the possible influences of treatment on the progression through the mitotic cycles were studied by analyzing lymphocyte proliferative kinetics. We observed that the percentage of apoptotic cells was higher as compared to necrotic ones in all time-points when irinotecan-treated samples were analyzed. Positive results obtained using both modifications of the comet assay indicate that in lymphocyte DNA following treatment with irinotecan a lot of single and double strand breaks are induced. Dynamics of damage infliction as observed both in alkaline and neutral modification of the comet assay clearly reflects the ’poisoning’ of the topoisomerase I, reported as the main mechanism of the irinotecan cytotoxicity. After treatment with irinotecan we observed an almost 7-fold increase of SCE frequency in exposed as compared to untreated lymphocytes that was obviously caused by topoisomerase poisoning in S-phase. Considering the results obtained we can conclude that irinotecan caused a delay of in vitro cell proliferation in first mitotic cycle. Despite their limitations, the results of our study indicate that irinotecan in its therapeutic concentrations is able to cause significant amount of primary and residual DNA damage in human peripheral blood lymphocytes. We could assume that the actual levels of DNA damage produced in actively divided cells of patients treated with irinotecan are much higher as compared to those estimated in vitro, since DNA damaging potential of irinotecan in vivo is up to one thousand times higher due to effectively conversion to its more potent metabolite SN-38. Our results point to the significance of biomarker studies in non-target cells of cancer patients after successful chemotherapy since they could be a good predictive factor to detect sensitive subpopulations of patients with genome instability that have an increased risk for developing of secondary malignancies.Primjenom različitih biomarkera u uvjetima in vitro istraženi su genotoksični učinci terapijske koncentracije irinotekana (350 mg/m2) na limfocite periferne krvi. Razine primarnih oštećenja DNA u limfocitnoj DNA i dinamika njihovog popravka istraženi su primjenom komet testa u alkalnim i neutralnim uvjetima. Preživljenje limfocita i indukcija apoptoze nakon izlaganja stanica irinotekanu istraženi su istodobnom primjenom fluorescencijskog bojenja etidij-bromidom i akridin oranžom. Razine oštećenja DNA procijenjene su i s pomoću testa izmjena sestrinskih kromatida, a mogući učinci tretmana na progresiju mitotičkog ciklusa istraženi su analizom proliferacijske kinetike limfocita. Utvr|eno je da je postotak apoptoza u svim vremenima uzorkovanja i analize bio veći od postotka nekroza. Pozitivni rezultati dobiveni s obje modifikacije komet testa pokazuju da se u limfocitnoj DNA nakon tretmana irinotekanom inducira mnoštvo jednolančanih i dvolančanih lomova. Dinamika nastanka oštećenja uočena primjenom obje modifikacije komet testa, jasno upućuje na disfunkciju enzima topoizomeraze I, koje se navodi kao glavni mehanizam citotoksičnosti irinotekana. Nakon tretmana irinotekanom uočili smo gotovo sedmerostruki porast učestalosti SCE u izloženim limfocitima u odnosu na kontrolu, što upozorava na poremećenu funkciju topoizomeraze u S-fazi. Na osnovi rezultata zaključujemo da irinotekan uzrokuje zastoj proliferacije stanica u prvom mitotskom ciklusu in vitro. Dobiveni rezultati pokazuju da terapijske koncentracije irinotekana uzrokuju značajan porast oštećenja DNA i kromosoma u ljudskim limfocitima periferne krvi. Budući da su učinci irinotekana u uvjetima in vivo znatno pojačani metaboličkom pretvorbom u aktivni metabolit SN-38, možemo pretpostaviti da su razine oštećenja DNA u aktivno dijelećim stanicama u pacijenata liječenih primjenom irinotekana značajno više nego one utvr|ene u uvjetima in vitro. Rezultati upućuju i na važnost istraživanja biomarkera u ne-tumorskim stanicama pacijenata koji su liječeni primjenom kemoterapije jer takvi biomarkeri mogu biti dobri pretkazatelji u otkrivanju osjetljivih populacija pacijenata s nestabilnim genomom u kojih je prisutan veći rizik za razvoj sekundarnih karcinoma

Istraživanje genotoksičnih učinaka irinotekana na ljudskim limfocitima periferne krvi primjenom različitih biomarkera u uvjetima in vitro

In the present study a multi-biomarker approach was used to evaluate genotoxic effects of irinotecan administered in vitro in its therapeutic dose (350 mg/m2) on non-target cells, peripheral blood lymphocytes. The levels of primary DNA damage in lymphocyte genome and the dynamics of its removal were assessed using the alkaline and neutral comet assay. Lymphocyte viability and the induction of apoptosis following exposure to irinotecan were studied by simultaneous use of a fluorescent assay with ethidium bromide and acridine orange. The levels of residual DNA damage were assessed by SCE assay, while the possible influences of treatment on the progression through the mitotic cycles were studied by analyzing lymphocyte proliferative kinetics. We observed that the percentage of apoptotic cells was higher as compared to necrotic ones in all time-points when irinotecan-treated samples were analyzed. Positive results obtained using both modifications of the comet assay indicate that in lymphocyte DNA following treatment with irinotecan a lot of single and double strand breaks are induced. Dynamics of damage infliction as observed both in alkaline and neutral modification of the comet assay clearly reflects the ’poisoning’ of the topoisomerase I, reported as the main mechanism of the irinotecan cytotoxicity. After treatment with irinotecan we observed an almost 7-fold increase of SCE frequency in exposed as compared to untreated lymphocytes that was obviously caused by topoisomerase poisoning in S-phase. Considering the results obtained we can conclude that irinotecan caused a delay of in vitro cell proliferation in first mitotic cycle. Despite their limitations, the results of our study indicate that irinotecan in its therapeutic concentrations is able to cause significant amount of primary and residual DNA damage in human peripheral blood lymphocytes. We could assume that the actual levels of DNA damage produced in actively divided cells of patients treated with irinotecan are much higher as compared to those estimated in vitro, since DNA damaging potential of irinotecan in vivo is up to one thousand times higher due to effectively conversion to its more potent metabolite SN-38. Our results point to the significance of biomarker studies in non-target cells of cancer patients after successful chemotherapy since they could be a good predictive factor to detect sensitive subpopulations of patients with genome instability that have an increased risk for developing of secondary malignancies.Primjenom različitih biomarkera u uvjetima in vitro istraženi su genotoksični učinci terapijske koncentracije irinotekana (350 mg/m2) na limfocite periferne krvi. Razine primarnih oštećenja DNA u limfocitnoj DNA i dinamika njihovog popravka istraženi su primjenom komet testa u alkalnim i neutralnim uvjetima. Preživljenje limfocita i indukcija apoptoze nakon izlaganja stanica irinotekanu istraženi su istodobnom primjenom fluorescencijskog bojenja etidij-bromidom i akridin oranžom. Razine oštećenja DNA procijenjene su i s pomoću testa izmjena sestrinskih kromatida, a mogući učinci tretmana na progresiju mitotičkog ciklusa istraženi su analizom proliferacijske kinetike limfocita. Utvr|eno je da je postotak apoptoza u svim vremenima uzorkovanja i analize bio veći od postotka nekroza. Pozitivni rezultati dobiveni s obje modifikacije komet testa pokazuju da se u limfocitnoj DNA nakon tretmana irinotekanom inducira mnoštvo jednolančanih i dvolančanih lomova. Dinamika nastanka oštećenja uočena primjenom obje modifikacije komet testa, jasno upućuje na disfunkciju enzima topoizomeraze I, koje se navodi kao glavni mehanizam citotoksičnosti irinotekana. Nakon tretmana irinotekanom uočili smo gotovo sedmerostruki porast učestalosti SCE u izloženim limfocitima u odnosu na kontrolu, što upozorava na poremećenu funkciju topoizomeraze u S-fazi. Na osnovi rezultata zaključujemo da irinotekan uzrokuje zastoj proliferacije stanica u prvom mitotskom ciklusu in vitro. Dobiveni rezultati pokazuju da terapijske koncentracije irinotekana uzrokuju značajan porast oštećenja DNA i kromosoma u ljudskim limfocitima periferne krvi. Budući da su učinci irinotekana u uvjetima in vivo znatno pojačani metaboličkom pretvorbom u aktivni metabolit SN-38, možemo pretpostaviti da su razine oštećenja DNA u aktivno dijelećim stanicama u pacijenata liječenih primjenom irinotekana značajno više nego one utvr|ene u uvjetima in vitro. Rezultati upućuju i na važnost istraživanja biomarkera u ne-tumorskim stanicama pacijenata koji su liječeni primjenom kemoterapije jer takvi biomarkeri mogu biti dobri pretkazatelji u otkrivanju osjetljivih populacija pacijenata s nestabilnim genomom u kojih je prisutan veći rizik za razvoj sekundarnih karcinoma

Karakteristike raka dojke ovisno o statusu mutacija u genima BRCA1 i BRCA2 u Hrvatskoj

Breast cancer (BC) represents 25% of all malignancies in Croatian women, and in 18.8% of cases, it is diagnosed before the age of 50. Croatia launched BRCA testing of people at increased family risk. Hereditary BC is mainly caused by a pathogenic mutation in the BRCA1 or BRCA2 gene and is a significant risk factor for developing breast and ovarian cancer. The present study included 127 women diagnosed with BC, with a strong family history of BC and the known status of the germline mutations in the BRCA1/BRCA2 genes. The majority of women were BRCA1/2 mutation non-carriers, while 15.7% were BRCA1/2 mutation carriers, and 4% had a variant of unknown significance (VUS). BRCA1/2 mutation carriers were younger than non-carriers (median 38.5 years vs. 44 years) (P=.01) and had tumors of higher histological grade (P<.001). The intrinsic subtype of BC differs significantly depending on the type of mutation (P<.001). Triple-negative BC prevailed (87.5%) in BRCA1 mutation carriers, and 12.5% had a luminal B/HER2-negative BC. Four patients were BRCA2 mutation carriers, and two of them had luminal B/HER2-positive BC. Most BRCA1/2 non-carriers (69.2%) and all VUS-carriers have luminal B/HER2-negative BC. Our results show that BRCA1/2 mutation testing is essential for women with a family history burden. It is a piece of valuable information in breast cancer risk assessment and contributes to early diagnosis.Rak dojke predstavlja 25% svih zloćudnih bolesti u žena u Hrvatskoj, a u 18,8% slučajeva dijagnosticira se prije 50. godine života. Nasljedni rak dojke uglavnom je uzrokovan patogenom mutacijom u genima BRCA1 ili BRCA2 te predstavlja glavni čimbenik rizika za razvoj raka dojke i jajnika. Stoga je Hrvatska pokrenula testiranje mutacija u genima BRCA1 i BRCA2 kod osoba koje, prema smjernicama za genetičko testiranje, imaju povećani obiteljski rizik. Ovo retrospektivno istraživanje obuhvatilo je 127 žena s pozitivnom obiteljskom anamnezom i utvrđenim statusom mutacija u genima BRCA1 i BRCA2, kojima je dijagnosticiran rak dojke. Većina žena nisu bile nositeljice mutacija u genima BRCA1 ili BRCA2 (BRCA1/2), dok je 15,7% bilo nositeljica mutacije BRCA1/2, a 4% je imalo varijantu nepoznatog značaja (VUS). Nositeljice mutacije BRCA1/2 bile su mlađe od ne-nositeljica (medijan 38,5 godina u odnosu na 44 godine) (P=.01) te su imale tumore višeg histološkog gradusa (P<.001). Intrinzični podtip raka dojke značajno se razlikuje ovisno o tipu mutacije (P<.001). Trostruko negativni podtip raka dojke prevladao je u nositeljica mutacija u BRCA1 (87,5%), a 12,5% imalo je luminalni B/HER2-negativni podtip. Četiri bolesnice bile su nositeljice mutacija u BRCA2 genu, od kojih dvije s luminalnim B/HER2-pozitivim rakom dojke. Većina bolesnica (69,2%) koje nisu nositeljice patoloških mutacija BRCA1/2 i sve one s VUS imale su luminalni B/HER2-negativni podtip raka dojke. Naši rezultati pokazuju da je testiranje mutacija u genima BRCA neophodno za žene s opterećenom obiteljskom anamnezom jer može igrati vitalnu ulogu u procjeni rizika od raka dojke i doprinjeti ranoj dijagnozi

Radioprotektivni učinci amifostina i melatonina na ljudske limfocite izložene gama-zračenju u uvjetima in vitro

Radioprotective effects of amifostine and melatonin as well as their ability to modulate the level of spontaneous and gamma-irradiation-induced genetic changes on human peripheral blood lymphocytes were investigated using the cytokinesis-block micronucleus (CBMN) assay and sister chromatid exchange (SCE). Parallel blood samples were pre-treated with amifostine, melatonin and their combination for 30 minutes. Negative controls were also included. After the treatment with radioprotectors, one blood sample of each experimental group was exposed to gamma-rays from a 60Co source. The radiation dose absorbed was 2 Gy. Our research confirmed the radioprotective effects of both chemicals in vitro, with no significant genotoxicity. Pre-treated irradiated blood samples showed a decrease in the total number of micronuclei (MN) and in the number of cells with more than one MN. They also showed significantly lower mean SCE values. This study shows that it is possible combine these radioprotectors by adjusting the doses of amifostine to achieve the best radioprotective effect with as few side effects as possible. However, further in vitro and clinical studies are needed to clarify their mechanisms of action and possible interactions.Primjena zračenja u liječenju zloćudnih bolesti (radioterapija) značajno pridonosi preživljenju bolesnika, ali izaziva i niz neželjenih učinaka na zdrave stanice i tkiva. Nuspojave ionizirajućeg zračenja mogu se značajno smanjiti s pomoću kemijskih spojeva s antioksidativnim učinkom koji djeluju kao ‘hvatači’ slobodnih radikala i štite vrlo osjetljivu molekulu DNA. Među spojeve s pretpostavljenim ili dokazanim radioprotektivnim učincima ubrajaju se amifostin i melatonin, koji su predmet istraživanja ovog rada. U literaturi nema dovoljno podataka o njihovoj genotoksičnosti ni međusobnim interakcijama. Stoga smo primjenom mikronukleusnog testa i analize izmjena sestrinskih kromatida (SCE) u uvjetima in vitro istražili djelovanje amifostina i melatonina na genom neozračenih i ozračenih ljudskih limfocita periferne krvi. Pojedinačno ili u kombinaciji, amifostin i melatonin dodavani su u uzorke pune krvi 30 minuta prije jednokratnog ozračivanja gama-zrakama izvora 60Co. Doza zračenja iznosila je 2 Gy, a koncentracije radioprotektora odgovaraju onima prije upotrebljavanim u kliničkoj primjeni ili u preliminarnim istraživanjima na ljudskoj populaciji. Ozračena krv kultivirana je 72 h u uvjetima in vitro prema standardnim protokolima za mikronukleusni test i test izmjena sestrinskih kromatida. Učinci amifostina i melatonina usporedo su istraživani i na kontrolnim, neozračenim uzorcima krvi. Dobiveni rezultati upućuju na značajno smanjenje ukupnog broja mikronukleusa i smanjenje udjela stanica s više od jednog mikronukleusa te sniženje ukupnog broja i raspona izmjena sestrinskih kromatida u pretretiranim uzorcima krvi. Potvrđen je vrlo dobar radioprotektivni učinak svakog spoja testiranog posebno, a ujedno je utvrđeno da oba spoja sinergistički djeluju na snižavanje razina oštećenja izazvanih u genomu limfocita pod utjecajem gama-zraka. S obzirom na to da primjenom citogenetičkih testova nije dokazana genotoksičnost navedenih radioprotektora za ljudske limfocite u uvjetima in vitro, dobiveni rezultati govore u prilog daljnjih istraživanja ovih spojeva i njima srodnih tvari u uvjetima in vivo te njihove moguće zajedničke primjene u kliničkoj praksi

Histopatološke karakteristike raka dojke od 2005 do 2019 u jednom centru u Hrvatskoj: pregled promjena nakon uvođenja mammografskog probira

INTRODUCTION: Croatia launched the National program for the early detection of breast cancer (BC) in 2006. The program targets women between the age of 50 and 69 to take a mammogram every two years. About 60% of women performed mammography through the program. The study aimed to determine the difference in breast cancer’s pathohistologic features before and after the introduction of screening. MATERIALS AND METHODS: Data was collected retrospectively in a single high volume center for women diagnosed with invasive BC in the period before the introduction of mammography screening (2005-2007; N=1833), and from newly diagnosed (2017-2019; N=2676). Statistical significance of the findings was evaluated using Chi square test. RESULTS: We recorded a 31.5% increase in the number of patients referred to our hospital in the post-screening period. However, no statistically significant reduction in tumor size, histological grade or the number of positive axillary lymph nodes was detected in newly diagnosed BC compared to those diagnosed over ten years ago. The mean age of BC incidence was 61 years, with the mean tumor size of 22 mm (median 18 mm), in both periods. The significant difference occurred in the distribution of the intrinsic subtypes of BC (P<.001). About 45% of patients were diagnosed with pT1N0 stage, in both periods. CONCLUSION: In the post-screening period, we treated 32% more newly diagnosed breast cancers. However, pathohistological features of BC, along with the average tumor size, did not change.UVOD: Nacionalni program za mamografski probir raka dojke u Hrvatskoj započeo je 2006, s ciljem otkrivanja raka u ranijem stadiju bolesti. Program uključuje mamografski pregled žena u dobi od 50 do 69. Cilj našeg istraživanja je utvrditi razlike u patohistološkim karakteristikama raka dojke prije uvođenja probira s novodijagnosticiranim. MATERIJALI I METODE: Retrospektivno smo u jednom centru prikupili podatke o patohistološkim karakteristikama raka dojke bolesnica oboljelih na početku mamografskog probira (2005-2007; N=1833) i podatke o novooboljelima iz razdoblja više od deset godina nakon uvedenog probira (2017-2019; N=2676). Dobivene podatke analizirali smo upotrebom χ2 testa. REZULTATI: Zbrinuli smo 31.5% više novodijagnosticiranih bolesnica s karcinomom dojke. Naši rezultati nisu pokazali statistički značajne razlike u veličini tumora, histološkom gradusu ili pozitivnom status limfnih čvorova u podpazušnoj jami u skupini novodijagnosticiranih bolesnica s karcinomom dojke u usporedbi s onima iz razdoblja prije mamografskog probira. Prosječna dob oboljevanja je 61 godina s prosječnom veličinom tumora od 22 mm (medijan 18 mm), u oba razdoblja. Oko 45 % bolesnica je dijagnosticirano s pT1N0, u oba razdoblja. ZAKLJUČAK: U razdoblju nakon uvođenja probira zbrinuli smo 32% više oboljelih od raka dojke u našoj instituciji. Nismo zabilježili razlike u patohistološkim karakteristikama tumora, niti u prosječnoj veličini tumora između ova dva perioda

Cytogenetic Follow-Up in Testicular Seminoma Patients Exposed to Adjuvant Radiotherapy

Early stage testicular seminoma is a radiosensitive tumor. Its incidence has significantly increased during the last decade especially in the young population. Although the therapy for testicular seminoma gives very satisfying results, the evaluation of genome damage caused by the therapy is of a great importance in order to recognize possible related health risks. The present study was performed on ten patients diagnosed with seminoma stage I; pT1/2N0M0S0, treated with adjuvant radiotherapy (a radiation dose of 25 Gy divided in 16 fractions) after orchidectomy. To assess the possible existence of an increased baseline DNA/chromosome damage in patients we also selected the appropriate control group of ten healthy men. The levels of primary DNA/chromosome damage in peripheral blood lymphocytes, as well as the dynamics of their repair were studied using the alkaline comet assay, chromosome aberration and cytokinesis-block micronucleus assay. Altogether four blood samples per patient were collected in the course of the therapy: before and after receiving the first dose of radiotherapy, in the middle of the radiotherapy cycle, and after the last dose of radiotherapy. Other two follow-up blood samples were collected six and twelve months after the cessation of therapy. As observed, the administration of the first radiation dose significantly increased the levels of DNA damage in almost all patients compared to their baseline values. Specific patterns of DNA damage were recorded in samples analyzed in the middle of radiotherapy and after receiving the last dose, indicating the possibility of an adaptive response in some patients. The levels of chromosomal aberrations and the incidence of micronuclei also increased in the course of therapy but gradually declined during the follow-up period. Our results confirmed the existence of post-irradiation damage in peripheral blood lymphocytes (and possibly in other non-target cells) of cancer patients which may represent a risk for the secondary cancer development. Considering that the majority of patients with testicular cancer are of a younger age, they represent a population deserving special attention. As cytogenetic screening may detect high-risk individuals, it might be useful in regular medical monitoring of seminoma patients after the successful therapy

Cytogenetic Follow-Up in Testicular Seminoma Patients Exposed to Adjuvant Radiotherapy

Early stage testicular seminoma is a radiosensitive tumor. Its incidence has significantly increased during the last decade especially in the young population. Although the therapy for testicular seminoma gives very satisfying results, the evaluation of genome damage caused by the therapy is of a great importance in order to recognize possible related health risks. The present study was performed on ten patients diagnosed with seminoma stage I; pT1/2N0M0S0, treated with adjuvant radiotherapy (a radiation dose of 25 Gy divided in 16 fractions) after orchidectomy. To assess the possible existence of an increased baseline DNA/chromosome damage in patients we also selected the appropriate control group of ten healthy men. The levels of primary DNA/chromosome damage in peripheral blood lymphocytes, as well as the dynamics of their repair were studied using the alkaline comet assay, chromosome aberration and cytokinesis-block micronucleus assay. Altogether four blood samples per patient were collected in the course of the therapy: before and after receiving the first dose of radiotherapy, in the middle of the radiotherapy cycle, and after the last dose of radiotherapy. Other two follow-up blood samples were collected six and twelve months after the cessation of therapy. As observed, the administration of the first radiation dose significantly increased the levels of DNA damage in almost all patients compared to their baseline values. Specific patterns of DNA damage were recorded in samples analyzed in the middle of radiotherapy and after receiving the last dose, indicating the possibility of an adaptive response in some patients. The levels of chromosomal aberrations and the incidence of micronuclei also increased in the course of therapy but gradually declined during the follow-up period. Our results confirmed the existence of post-irradiation damage in peripheral blood lymphocytes (and possibly in other non-target cells) of cancer patients which may represent a risk for the secondary cancer development. Considering that the majority of patients with testicular cancer are of a younger age, they represent a population deserving special attention. As cytogenetic screening may detect high-risk individuals, it might be useful in regular medical monitoring of seminoma patients after the successful therapy