K-ras, p53 mutations, and microsatellite instability (MSI) in gallbladder cancer

Despite the considerable progress in understanding the molecular pathology of carcinogenesis, the genetic mechanisms underlying the development and progression of gallbladder cancer (GC) are poorly understood. The survival of GC patients is generally poor. Therefore, it is very useful to define valuable prognostic factors. The most extensively studied oncogenes in gallbladder carcinogenesis are ras, commonly mutated in neoplasms of the gastrointestinal tract. K-ras oncogene is altered in a subset of gallbladder patients and mainly in those having anomalous junction of the pancreaticobiliary tract. Most of the studies of genetic abnormalities in GC have focused on p53 gene. p53 mutation/overexpression and/or LOH is present in more than 50% of gallbladder carcinomas, suggesting an important role in their pathogenesis. However, these results have not any predictive value yet. Moreover, the involvement of an alternative molecular pathway, that of microsatellite instability (MSI), is found in a limited group of GC patients. Additional research is necessary to establish its possible relation to defects of the mismatch repair (MMR) system and its proposed prognostic significance. Further elucidation of the molecular events specific to GC will help to identify novel molecular targets for the diagnosis and clinical management of the patients

mRNA coexpression patterns of Wnt pathway components and their clinicopathological associations in breast and colorectal cancer

Aberrant Wnt signaling is implicated in carcinogenesis triggering efforts for the development of new therapeutic agents, many of which have entered clinical trials. We extend our previous analysis of WNT3, FZD7, LEFI expression levels in breast and colorectal cancer including WNT2, FZD4 and beta-catenin expression, in an effort to delineate their relative expression levels along with concurrent expression patterns and possible prognostic value. We analyzed 82 breast and 102 colorectal carcinomas for relative mRNA expression levels of the investigated genes by RT-PCR relative quantification with the Delta Delta Ct method. Statistical analysis was performed in order to determine associations of relative mRNA expression and linear correlations. beta-catenin expression was determined by immunochemistry. Regarding breast carcinomas, decreased relative mRNA expression levels of WNT2, FZD4 were found frequently and WNT2 expression was correlated with ER/ PR status (p = 0.045/p = 0.028), whereas beta-catenin with grade (p = 0.026). In colorectal carcinomas, increased relative mRNA expression levels of WNT2 and FZD4 were found in 59% and 32% of cases respectively, whereas beta-catenin showed decreased mRNA expression levels in 57% of cases and a correlation with pN-category (p = 0.037). Linear correlations were observed between WNT2/FZD4 (R=0.542, p < 0.001), WNT2/beta-catenin (R=0.254, p = 0.010), FZD4/beta-catenin (R=0.406, p < 0.001) expression and a correlation between mRNA expression and membranous/cytoplasmic beta-catenin emerged (p = 0.039/0.046). Our results suggest a possible clinical significance for Wnt pathway gene expression levels in both tumour types. The concurrent expression of the investigated genes as well as the different expression profiles, underlines the complexity of this pathway and the necessity of patient selection in order to maximize the efficacy of drugs targeting Wnt pathway

Comprehensive Molecular Analysis of NSCLC; Clinicopathological Associations

Background Selection of NSCLC patients for targeted therapy is currently based upon the presence of sensitizing mutations in EGFR and EML4/ALK translocations. The heterogeneity of molecular alterations in lung cancer has led to the ongoing discovery of potential biomarkers and targets in order to improve survival. Aim This study aimed to detect alterations in EGFR, KRAS, BRAF, PIK3CA, MET-gene copy number and ALK rearrangements in a large cohort of 956 NSCLC patients of Hellenic origin using highly sensitive techniques and correlations with clinicopathological characteristics. Results Mutations were detected in EGFR 10.6%(101 out of 956 samples), KRAS 26.5% (191 out of 720 samples), BRAF 2.5% (12 out of 471 samples), PIK3CA 3.8% (7 out of 184 samples), MET gene amplification was detected in 18% (31 out of 170) and ALK rearrangements in 3.7% (4 out of 107 samples). EGFR mutations were detected in exon 19 (61.4% of mutant cases), exon 21 p.Leu858Arg (19.8%), exon 20 (15.8%), exon 18 (2.9%) and were correlated with gender histology, smoking status and TTF1 staining. p.Thr790Met mutant cases (3.9%) displayed concurrent mutations in exons 19 or 21. Negative TTF-1 staining showed strong negative predictive value for the presence of EGFR mutations. KRAS mutations were associated with histology, the most common mutation being p.Gly12Cys (38%). Discussion In conclusion, only 89 patients were eligible for EGFR-TKIs and ALK inhibitors therapy, whereas 257 patients showed other alterations, highlighting the necessity for a detailed molecular profiling potentially leading to more efficient individualized therapies for NSCLC patients

Comprehensive Molecular Analysis of NSCLC; Clinicopathological Associations.

Selection of NSCLC patients for targeted therapy is currently based upon the presence of sensitizing mutations in EGFR and EML4/ALK translocations. The heterogeneity of molecular alterations in lung cancer has led to the ongoing discovery of potential biomarkers and targets in order to improve survival.This study aimed to detect alterations in EGFR, KRAS, BRAF, PIK3CA, MET-gene copy number and ALK rearrangements in a large cohort of 956 NSCLC patients of Hellenic origin using highly sensitive techniques and correlations with clinicopathological characteristics.Mutations were detected in EGFR 10.6% (101 out of 956 samples), KRAS 26.5% (191 out of 720 samples), BRAF 2.5% (12 out of 471 samples), PIK3CA 3.8% (7 out of 184 samples), MET gene amplification was detected in 18% (31 out of 170) and ALK rearrangements in 3.7% (4 out of 107 samples). EGFR mutations were detected in exon 19 (61.4% of mutant cases), exon 21 p.Leu858Arg (19.8%), exon 20 (15.8%), exon 18 (2.9%) and were correlated with gender histology, smoking status and TTF1 staining. p.Thr790Met mutant cases (3.9%) displayed concurrent mutations in exons 19 or 21. Negative TTF-1 staining showed strong negative predictive value for the presence of EGFR mutations. KRAS mutations were associated with histology, the most common mutation being p.Gly12Cys (38%).In conclusion, only 89 patients were eligible for EGFR -TKIs and ALK inhibitors therapy, whereas 257 patients showed other alterations, highlighting the necessity for a detailed molecular profiling potentially leading to more efficient individualized therapies for NSCLC patients

A detailed immunohistochemical analysis of the PI3K/AKT/mTOR pathway in lung cancer: Correlation with PIK3CA, AKT1, K-RAS or PTEN mutational status and clinicopathological features

The phosphoinositide 3-kinase (PI3K)/v-akt murine thymoma viral oncogene homolog (AKT)/mammalian target of rapamycin (mTOR) pathway is upregulated in a number of human cancers, including non-small cell lung cancer (NSCLC). Its potential role in NSCLC progression provides an attractive target for anticancer therapy. The expression of phosphorylated mTOR (p-mTOR), phosphorylated AKT (p-AKT), p85 alpha and p110 gamma subunits of PI3K, phosphorylated p70S6K (p-p70S6K), phosphatase and tensin homolog (PTEN) and phosphorylated 4E-BP1 (p-4E-BP1) was examined by immunohistochemistry in 102 NSCLC specimens. The results were correlated with clinicopathological features. We also examined 61 of our cases for the presence of PIK3CA, AKT1, PTEN and K-RAS mutations. A common PIK3CA mutation was detected at exon 9 in 2 samples (p.E545K), whereas another sample displayed a rare mutation (p.D1018N). Furthermore, 10 out of 54 cases (18.5%) had a K-RAS mutation at codon 12, 5 had a PTEN mutation (exons 7 and 8) and 1 case had an AKT1 mutation (p.E17K). PTEN mutations were associated with nodal metastases. The expression of p-mTOR positively correlated with that of p-AKT and p-p70S6K and was higher in adenocarcinomas along with nuclear p110 gamma PI3K expression, whereas p-4E-BP1 expression was higher in squamous cell carcinomas. We also established a positive association between p85 alpha PI3K or p110 gamma PI3K and cytoplasmic p-AKT and its downstream effectors. An inverse correlation was noted between p-4E-BP1 immunoexpression and tumour status and nuclear p-AKT expression as regards tumour stage. Univariate survival analysis demonstrated that p-4E-BP1 expression, either alone or in combination with cytoplasmic p-AKT expression had an adverse prognostic significance in adenocarcinomas. The combination of p-4E-BP1 and cytoplasmic p-AKT expression remained significant in the multivariate analysis as a function of their interaction with histological type. Our data demonstrate the significance of p-4E-BP1 immunoexpression as a molecular marker of prognostic value in adenocarcinomas, particularly when combined with p-AKT

MTOR/4EBP1 signaling and MMR status in colorectal cancer: New correlations and arising perspectives

This is the first study aiming to investigate mTOR signaling and its relation to mismatch repair status (MMR status) in colorectal cancer (CRC). MMR status and the phosphorylated proteins, pmTOR and p4EBP1, have been immunohistochemically analyzed in 108 formalin-fixed, paraffin-embedded CRC specimens. The correlations between them and with clinicopathological data, MAPK pathway (KRAS, NRAS, BRAF) as well as their impact on patients’ overall survival have been statistically analyzed. Our results indicated that positive pmTOR expression was significantly associated with KRAS mutations (p = 0.004). From multivariate survival analysis, only p4EBP1 expression emerged as independent adverse prognostic factor for overall survival (HR, 3.322; 95%CI, 1.110-9.945; p = 0.032). Furthermore, MMR deficient carcinomas tend to express low p4EBP1 protein levels (p = 0.002). A survival analysis stratified by MMR status and p4EBP1 expression, showed that MMR proficient tumours with high p4EBP1 expression had the worst overall survival compared with the other examined subgroups (p = 0.019). In conclusion, MAPK and PI3k/Akt pathways seem to be simultaneously overactivated in CRC. P4EBP1 could be used as a prognostic biomarker. By further analyzing the significant association between MMR status and p4EBP1 expression, we suggest that MMR deficient tumours could represent a subpopulation most likely to derive treatment benefit from mTOR inhibition