PIK3CA alterations in Middle Eastern ovarian cancers

<p>Abstract</p> <p>Background</p> <p>PI3K/AKTsignaling pathway plays an important role in cell growth, proliferation, and tumorgenesis of various malignancies. This signaling pathway has been shown to be frequently altered in several human cancers including ovarian cancers. However the role of this oncogenic signaling pathway has not been explored in the Middle Eastern epithelial ovarian cancer (EOC). Therefore, we investigated PI3K/AKT genetic alterations such as PIK3CA amplification, PIK3CA mutation, PTEN protein loss and their relationships with various clinicopathological characteristics in 156 EOCs.</p> <p>Results</p> <p>Fluorescence <it>in situ </it>hybridization (FISH) technique and DNA sequencing were used to analyze PIK3CA amplification and mutation respectively. Expression of PIK3CA protein expression (p110 α), PTEN, p-AKT and Ki-67 was analyzed by immunohistochemistry. <it>PIK3CA </it>amplification was seen in 54 of 152 (35.5%) EOC cases analyzed; PIK3CA gene mutations in 6/153 EOC (3.9%); <it>KRAS </it>mutations in 3/154 EOC (1.9%), BRAF mutations in 3/156 EOC (1.9%), p53 mutation in 50/154 EOC (32.5%), and loss of PTEN protein expression in 33/144 EOC (22.9%). p110 α overexpression was associated with increased phosphorylation of AKT-Ser 473 and with the proliferation marker Ki-67.</p> <p>Conclusion</p> <p>Our data showed mutual exclusivity between the molecular event of PIK3CA amplification and mutations in <it>PIK3CA</it>, <it>KRAS</it>, <it>BRAF </it>genes, which suggests that each of these alterations may individually be sufficient to drive ovarian tumor pathogenesis independently. High prevalence of genetic alterations in PI3K/AKT pathway in a Middle Eastern ovarian carcinoma provides genetic evidence supporting the notion that dysregulated PI3K/AKT pathways play an important role in the pathogenesis of ovarian cancers.</p

Predictive risk factors for distant metastasis in pediatric differentiated thyroid cancer from Saudi Arabia

BackgroundDespite their excellent prognosis, children and young adults (CAYA) with differentiated thyroid cancer (DTC) tend to have more frequent occurrence of distant metastasis (DM) compared to adult DTC. Data about DM in CAYA from Middle Eastern ethnicity is limited.MethodsMedical records of 170 patients with DTC ≤18 years were retrospectively reviewed. Clinico-pathological factors associated with lung metastasis in CAYA, their clinical presentation and outcome were analyzed. Rick factors related to distant metastasis-free survival (DMFS) for the whole cohort were evaluated.ResultsDM was observed in 27 patients and all were lung metastasis. Lung metastasis was significantly associated with younger age (≤15 years), extrathyroidal extension (ETE), multifocal tumors, bilaterality, presence of lymph node (LN) disease and high post-operative stimulated thyroglobulin (sTg). Highest negative predictive values were seen with low post-operative sTg (97.9%), absence of LN disease (93.8%), absence of ETE (92.2%) and age older than 15 years (92.9%). Post-therapy whole body scan (WBS) identified most of the lung metastasis (21 of 27; 77.8%). Upon evaluating patients response according to ATA guidelines, excellent response was seen in only one patient, while biochemical persistence and structural persistence were seen in 11.1% (3/27) and 77.8% (21/27), respectively. Elevated post-operative sTg (&gt;10ng/ml) was the only risk factor found to be significantly associated with both biochemical persistence (with or without structural persistence (p = 0.0143)) and structural persistence (p = 0.0433). Cox regression analysis identified age and post-operative sTg as independent risk factors related to DMFS. Based on these two risk factors for DMFS, patients were divided into 3 groups: low risk (no risk factors), intermediate risk (1 risk factor) and high risk (both risk factors). 20-year DMFS rates in the low-, intermediate- and high-risk groups were 100.0%, 81.3% and 23.7% respectively (p &lt; 0.0001).ConclusionHigher suspicion for metastatic pediatric DTC should be considered in patients who are young, have LN disease, extrathyroidal extension and elevated post-operative sTg. Persistent disease, despite therapy, is very common and it appears to be related to post-operative sTg level. Hence, risk adaptive management is desirable in CAYA with DTC

Constitutional mismatch repair-deficiency syndrome is a rare cause of cancer even in a highly consanguineous population

Biallelic germline mutations in the mismatch repair genes, including MLH1, MSH2, MSH6 or PMS2, lead to a recessive constitutional mismatch repair-deficiency (CMMR-D) syndrome characterized by early onset malignancies in children and young adults. Because consanguinity unmasks autosomal recessive disorders, we hypothesized that the frequency of CMMR-D is inflated in the highly consanguineous population of Saudi Arabia. In this study, 371 pediatric and young adult patient samples from Saudi Arabia that cover the tumor spectrum of CMMR-D syndrome were analyzed for biallelic germline mutations in the MLH1, MSH2, MSH6 and PMS2 with the use of direct genomic sequencing. However, none of the 371 patients involved in the study was found to have biallelic pathological mutations of MLH1, MSH2, MSH6 or PMS2. This result indicates that CMMR-D is exceptionally rare among pediatric cancer patients and adult early onset cancer patients, even in the highly consanguineous Saudi population. Our findings suggest that larger cohorts will be needed, particularly in outbred populations, to determine the frequency of CMMR-D and that routine screening for this syndrome among cancer patients is not warranted

PD-L1 Expression Is Associated with Deficient Mismatch Repair and Poor Prognosis in Middle Eastern Colorectal Cancers

Several clinical trials are investigating the use of immune-targeted therapy with Programmed death ligand-1 (PD-L1) inhibitors for colorectal cancer (CRC), with promising results for patients with mismatch repair (MMR) deficiency or metastatic CRC. However, the prognostic significance of PD-L1 expression in CRC is controversial and such data are lacking in CRC from Middle Eastern ethnicity. We carried out this large retrospective study to investigate the prognostic and clinico-pathological impact of PD-L1 expression in Middle Eastern CRC using immunohistochemistry. A total of 1148 CRC were analyzed for PD-L1 expression. High PD-L1 expression was noted in 37.3% (428/1148) cases and was correlated with aggressive clinico-pathological features such as high malignancy grade (p p = 0.0007) and mucinous histology (p = 0.0005). Interestingly, PD-L1 expression was significantly higher in patients exhibiting MMR deficiency (p = 0.0169) and BRAF mutation (p = 0.0008). Furthermore, the expression of PD-L1 was found to be an independent marker for overall survival (HR = 1.45; 95% CI = 1.06–1.99; p = 0.0200). In conclusion, the results of this study indicate that PD-L1 expression could be a valid biomarker for poor prognosis in Middle Eastern CRC patients. This information can help in decision-making for anti-PD-L1 therapy in Middle Eastern CRC, especially for patients with MMR deficient tumors

Identification and characterization of ATM founder mutation in BRCA-negative breast cancer patients of Arab ethnicity

Abstract Breast cancer (BC) is the most prevalent malignancy among women worldwide with germline pathogenic variants/likely pathogenic variants (PVs/LPVs) in BRCA1/2 accounting for a large portion of hereditary cases. Recently, heterozygous PVs/LPVs in the ATM serine/threonine kinase or Ataxia-telangiectasia mutated gene (ATM) has been identified as a moderate susceptibility factor for BC in diverse ethnicities. However, the prevalence of ATM PVs/LPVs in BC susceptibility in Arab populations remains largely unexplored. This study investigated the prevalence of ATM PVs/LPVs among BC patients from Saudi Arabia, employing capture-sequencing technology for ATM PVs/LPVs screening in a cohort of 715 unselected BC patients without BRCA1/2 PVs/LPVs. In addition, founder mutation analysis was conducted using the PHASE program. In our entire cohort, four unique PVs/LPVs in the ATM gene were identified in six cases (0.8%). Notably, one recurrent LPV, c.6115G > A:p.Glu2039Lys was identified in three cases, for which haplotype analysis confirmed as a novel putative founder mutation traced back to 13 generations on average. This founder mutation accounted for half of all identified mutant cases and 0.4% of total screened cases. This study further reveals a significant correlation between the presence of ATM mutation and family history of BC (p = 0.0127). These findings underscore an approximate 0.8% prevalence of ATM germline PVs/LPVs in Arab BC patients without BRCA1/2 PVs/LPVs and suggest a founder effect of specific recurrent ATM mutation. These insights can help in the design of a genetic testing strategy tailored to the local population in Saudi Arabia, thereby, enabling more accurate clinical management and risk prediction

PLK1 and FoxM1 expressions positively correlate in papillary thyroid carcinoma and their combined inhibition results in synergistic anti‐tumor effects

Polo‐like kinase 1 (PLK1; also known as serine/threonine‐protein kinase PLK1) serves as a central player in cell proliferation, exerting critical regulatory roles in mitotic processes and cell survival. We conducted an analysis of PLK1 protein expression in a large cohort of samples from papillary thyroid carcinoma (PTC) patients and examined its functional significance in PTC cell lines, both in vitro and in vivo. PLK1 overexpression was noted in 54.2% of all PTC and was significantly associated with aggressive clinicopathological parameters; it was also found to be an independent prognostic marker for shorter recurrence‐free survival. Given the significant association between PLK1 and forkhead box protein M1 (FoxM1), and their concomitant overexpression in a large proportion of PTC samples, we explored their correlation and their combined inhibitions in PTC in vitro and in vivo. Inhibition of PLK1 expression indeed suppressed cell proliferation, leading to cell cycle arrest and apoptosis in PTC cell lines. Significantly, the downregulation of PLK1 reduced the self‐renewal capability of spheroids formed from PTC cells. Immunoprecipitation analysis shows that PLK1 binds to FoxM1 and vice versa in vitro. Mechanistically, PLK1 knockdown suppresses FoxM1 expression, whereas inhibition of FoxM1 does not affect PLK1 expression, which suggests that PLK1 acts through the FoxM1 pathway. The combined treatment of a PLK1 inhibitor (volasertib) and a FoxM1 inhibitor (thiostrepton) demonstrated a synergistic effect in reducing PTC cell growth in vitro and delaying tumor growth in vivo. This study highlights the important role of PLK1 in PTC tumorigenesis and prognosis. It also highlights the synergistic therapeutic potential of dual‐targeting PLK1 and FoxM1 in PTC, unveiling a potential innovative therapeutic strategy for managing aggressive forms of PTC

Overexpression of the pro‐protein convertase furin predicts prognosis and promotes papillary thyroid carcinoma progression and metastasis through RAF/MEK signaling

Furin belongs to the pro‐protein convertases (PCs) family and its aberrant expression has been documented in various types of cancers; however, its role in thyroid cancer remains unclear. We investigated the expression of furin in a large cohort of Middle Eastern papillary thyroid carcinoma (PTC) patient samples and explored its functional role and mechanism in PTC cell lines in vitro and in vivo. Furin overexpression was observed in 44.6% of all PTC cases and was significantly associated with aggressive clinicopathological parameters and poor outcomes. We show that the knockdown of FURIN suppresses tumor growth, proliferation, migration, invasion, spheroid growth, and progression of epithelial‐to‐mesenchymal transition (EMT) in B‐Raf proto‐oncogene, serine/threonine kinase (BRAF) mutant cells, whereas its overexpression in BRAF wild‐type PTC cell lines reversed the effect. FURIN knockdown in the BRAF mutant cell line led to reduced tumor growth and increased apoptosis. Mechanistically, FURIN knockdown led to MEK/ERK pathway suppression in BRAF mutant cells, although inhibition of MEK did not affect furin expression, which suggests that furin acts through the MEK/ERK pathway. Furthermore, our study revealed the synergistic antitumor effect of furin depletion and anti‐MEK inhibitor treatment. Overall, these results indicate that furin is an important prognostic marker in Middle Eastern PTC and that it plays a crucial role in BRAF‐associated MAP/ERK pathway activation and tumorigenesis. Furin inhibition could be a potential therapeutic target for aggressive PTC

PALB2 germline mutations in a large cohort of Middle Eastern breast-ovarian cancer patients

Abstract The PALB2 gene is a breast cancer (BC) and ovarian cancer (OC) predisposition gene involved in the homologous recombination repair pathway. However, the prevalence and clinicopathological association of PALB2 pathogenic/likely pathogenic (PV/LPV) variants in Middle East is still not fully explored. Total 918 BC/OC patients from Saudi Arabia were selected for PALB2 mutations screening using capture sequencing technology. Five heterozygous PVs or LPVs were identified in six cases, accounting for 0.65% (6/918) of entire cohort. Two cases (33.3%) harbored PVs and four cases (66.7%) carried LPVs. Four PVs/LPVs (80%) were frameshift along with one novel splicing LPV (c.2835-2_2835-1delinsTT). One recurrent LPV (c.3425delT: p.L1142fs) was identified in two cases. All six affected carriers have breast cancer diagnosis with median age of 39.5 years (range 34–49 years). Only two cases (33%) have documented family history of cancer. Breast cancer phenotype was invasive ductal unilateral cancer in all cases with 66.7% of hormone receptor positive and 16% of triple negative tumors. Germline PVs/LPVs in the PALB2 gene were observed in low frequency of 0.65% in Saudi BC and/or OC. Our study confirms one recurrent LPV and one novel LPV in Saudi breast cancer patients

DataSheet_1_Predictive risk factors for distant metastasis in pediatric differentiated thyroid cancer from Saudi Arabia.docx

BackgroundDespite their excellent prognosis, children and young adults (CAYA) with differentiated thyroid cancer (DTC) tend to have more frequent occurrence of distant metastasis (DM) compared to adult DTC. Data about DM in CAYA from Middle Eastern ethnicity is limited.MethodsMedical records of 170 patients with DTC ≤18 years were retrospectively reviewed. Clinico-pathological factors associated with lung metastasis in CAYA, their clinical presentation and outcome were analyzed. Rick factors related to distant metastasis-free survival (DMFS) for the whole cohort were evaluated.ResultsDM was observed in 27 patients and all were lung metastasis. Lung metastasis was significantly associated with younger age (≤15 years), extrathyroidal extension (ETE), multifocal tumors, bilaterality, presence of lymph node (LN) disease and high post-operative stimulated thyroglobulin (sTg). Highest negative predictive values were seen with low post-operative sTg (97.9%), absence of LN disease (93.8%), absence of ETE (92.2%) and age older than 15 years (92.9%). Post-therapy whole body scan (WBS) identified most of the lung metastasis (21 of 27; 77.8%). Upon evaluating patients response according to ATA guidelines, excellent response was seen in only one patient, while biochemical persistence and structural persistence were seen in 11.1% (3/27) and 77.8% (21/27), respectively. Elevated post-operative sTg (>10ng/ml) was the only risk factor found to be significantly associated with both biochemical persistence (with or without structural persistence (p = 0.0143)) and structural persistence (p = 0.0433). Cox regression analysis identified age and post-operative sTg as independent risk factors related to DMFS. Based on these two risk factors for DMFS, patients were divided into 3 groups: low risk (no risk factors), intermediate risk (1 risk factor) and high risk (both risk factors). 20-year DMFS rates in the low-, intermediate- and high-risk groups were 100.0%, 81.3% and 23.7% respectively (p ConclusionHigher suspicion for metastatic pediatric DTC should be considered in patients who are young, have LN disease, extrathyroidal extension and elevated post-operative sTg. Persistent disease, despite therapy, is very common and it appears to be related to post-operative sTg level. Hence, risk adaptive management is desirable in CAYA with DTC.</p