Characteristics of CD44 alternative splice pattern in the course of human colorectal adenocarcinoma progression

<p>Abstract</p> <p>Background</p> <p>CD44 is considered as ‘a’ metastasis associated gene, despite the fact that it is an umbrella term for a group of molecules produced from a single gene by alternative splicing. However, little consideration is given to the above in the literature of colorectal carcinomas as well as other tumour types, leading to confusion and contradictory results about its possible role in tumour progression.</p> <p>Methods</p> <p>We compared the CD44 alternative splice pattern (ASP) of three genetically different human colorectal cancer cell lines (HT25, HT29, HCT116) using a series of PCR reactions and next- generation sequencing method, as well as identified a colorectal adenocarcinoma specific CD44 ASP. This ASP was further investigated in terms of its qualitative and quantitative stability in our experimental iso- and xenograft mouse models for colorectal cancer progression. A complex preclinical experimental set-up was established to separately test the different steps of tumour progression and the role of tumour microenvironment, respectively, focusing on the role of ‘CD44’ in this process.</p> <p>Results</p> <p>We managed to present a colorectal cancer-specific CD44 ASP, which remained unchanged from cell lines throughout primary tumour formation and metastatic progression. Furthermore, we report a unique roster of all expressed CD44 variant isoforms characteristic to colorectal cancer. Finally, on quantitative assessment of the variable exons v3 and v6, higher co-expression levels were found to be characteristic to metastatically potent tumour cells.</p> <p>Conclusion</p> <p>Particular CD44 variant isoforms seem to act as “metastasis genes” via tumour microenvironment-driven shifts in v3 and v6 expressions. However, this function may just affect a minority of tumour subclones. This fact and the huge potential number of different CD44 splice variants that can contain v3 and v6 domains can explain incoherence of clinical studies regarding functional asessment of CD44 variants, as well as diminish the chances of using CD44 variants for predictive purpose.</p

A malignus melanóma prognosztikus és prediktív markerei

A malignus melanóma, bár megjelenését tekintve igen sokszínű, de biológiailag áttétképző és áttétet nem képző formákra osztható. A klasszikus klinikopatológiai faktoroknak a betegség lefolyását felbecsülő képessége limitált, ezért széleskörű kutatások történnek a melanóma progressziós markerei vonatkozásában. Bár sokféle genetikai vagy fehérjemintázatot azonosítottak, ezek klinikai haszna csekély, mert a vizsgálatok alig vették figyelembe a melanóma progressziója alapjainak megismerését célzó kutatások eredményeit, így az ígéretes markerek csoportja igen szűk (BCL2, CDK2, MART-1, OPN). Hasonlóan más szolid daganatokhoz, a célzott terápiák megjelenése ráirányította a figyelmet a melanóma kemo- és célzott terápiára mutatott rezisztenciájának genetikai alapjaira. Ezek az ismeretek új molekuláris patológiai eljárásokhoz és remélhetően hatékonyabb terápiás protokollok kialakításához adhatnak segítséget. | Malignant melanoma biologically can be divided into non-metastatic and metastatic forms which cannot be predicted precisely using classical clinicopathological parameters, therefore studies on novel genetic or protein markers are abundant in the literature. These studies did not result in clinically useful markers because mostly ignored the results of studies on the genetic basis of metastatic potential of malignant melanoma. Accordingly, the list of promising novel markers is short (BCL2, CDK2, MART-1, OPN). Similar to other solid malignancies, introduction of targeted therapy into clinical practice of melanoma turned the attention toward the genetic basis of resistance to chemo- and targeted therapies. These novel data could lead to the development of molecular diagnostics which can help in designing more effective therapeutic strategies of malignant melanoma

EGFR Autophosphorylation but Not Protein Score Correlates With Histologic and Molecular Subtypes in Lung Adenocarcinoma

Established clinicopathologic characteristics of non-small cell lung cancer patients define a subgroup responding better to EGFR-TK inhibitors: adenocarcinoma histology, ethnicity, sex, smoking status, presence of activating EGFR mutation, and/or K-RAS wild type. However, EGFR mutation does not automatically lead to increased activity of the protein influenced by several factors. As adenocarcinoma can be further divided into histologic subclasses, we compared adenocarcinomas without lepidic growth pattern (NLAC) to those characterized by pure or predominant lepidic growth (LAC) for EGFR protein expression and autophosphorylation activity (Y1173), as determined by immunohistochemistry. This pretarget therapy cohort comprised a total of 110 surgically operated patients of stage I non-small cell lung cancer: 49 NLAC and 61 LAC variants. The LAC group had a significantly better prognosis and the incidence of phospho-EGFR-positive tumors was significantly higher compared with NLAC. Patient sex did not influence EGFR activity, but the incidence of pEGFR-positive tumors was significantly lower among smoker patients. There was no statistically significant difference in EGFR or KRAS mutation frequencies between the 2 groups. In NLAC, pEGFR-positive tumors occurred exclusively among EGFR-mutant/K-RAS wild-type tumors. On the contrary, in LAC tumors, pEGFR-positive tumors were similarly frequent in the EGFR or K-RAS mutant groups indicating an interesting feedback activation of EGFR signaling in K-RAS mutant tumors. Our data also indicate that EGFR mutation leads to EGFR autophosphorylation only in a small fraction of adenocarcinoma patients, which might have clinical significance

Comparison of standard mismatch repair deficiency and microsatellite instability tests in a large cancer series

Abstract Background The tumor-agnostic indication of immune checkpoint inhibitors to treat cancers with mismatch repair deficiency (dMMR)/microsatellite instability (MSI) increased the demand for such tests beyond Lynch syndrome. International guideline recommendations accept immunohistochemistry (IHC) for dMMR or molecular techniques (PCR or NGS) for MSI status determinations considering the two tests are equal, although there are scattered reports contradicting to this presumption. Materials and methods Here we have directly compared four protein MMR immunohistochemistry (IHC) to MSI Pentaplex PCR test in a large cancer patient cohort (n = 1306) of our diagnostic center where the two tests have been run parallel in 703 cases. Results In this study we have found a high discrepancy rate (19.3%) of the two tests which was independent of the tumor types. The MSI PCR sensitivity for MMR IHC status was found to be very low resulting in a relatively low positive and negative predicting values. As a consequence, the correlation of the two tests was low (kappa < 0.7). During analysis of the possible contributing factors of this poor performance, we have excluded low tumor percentage of the samples, but identified dMMR phenotypes (classic versus non-classic or unusual) as possible contributors. Conclusion Although our cohort did not include samples with identified technical errors, our data strongly support previous reports that unidentified preanalytical factors might have the major influence on the poor performance of the MSI PCR and MMR IHC. Furthermore, the case is open whether the two test types are equally powerful predictive markers of immunotherapies