ERCC1 SNPs as Potential Predictive Biomarkers in Non-Small Cell Lung Cancer Patients Treated With Platinum-Based Chemotherapy.

Polymorphisms in ERCC1, XPD, and XRCC1 were examined for (a) association with the clinical outcome of 107 non-small cell lung cancer patients receiving front-line platinum-based chemotherapy, and (b) correlation with the ERCC1 mRNA levels of 176 chemo-naive primary tumors. The ERCC1-C8092 allele and the number of ERCC1 polymorphic variants (C8092A and Asn118Asn) were associated with progression-free survival. In non-squamous histology, tumoral ERCC1 mRNA levels were lower in patients homozygous for ERCC1-C8092 as compared with the patients carrying the A allele (p = .024). These findings merit investigation in larger cohorts of patients treated with uniform regimens.

KRAS genotypic changes of circulating tumor cells during treatment of patients with metastatic colorectal cancer.

INTRODUCTION: Circulating tumor cells (CTCs) could represent a non-invasive source of cancer cells used for longitudinal monitoring of the tumoral mutation status throughout the course of the disease. The aims of the present study were to investigate the detection of KRAS mutations in CTCs from patients with metastatic colorectal cancer (mCRC) and to compare their mutation status during treatment or disease progression with that of the corresponding primary tumors. MATERIALS AND METHODS: Identification of the seven most common KRAS mutations on codons 12 and 13 was performed by Peptide Nucleic Acid (PNA)-based qPCR method. The sensitivity of the assay was determined after isolation of KRAS mutant cancer cells spiked into healthy donors' blood, using the CellSearch Epithelial Cell kit. Consistent detection of KRAS mutations was achieved in samples containing at least 10 tumor cells/7.5 ml of blood. RESULTS: The clinical utility of the assay was assessed in 48 blood samples drawn from 31 patients with mCRC. All patients had PIK3CA and BRAF wild type primary tumors and 14 KRAS mutant tumors. CTCs were detected in 65% of specimens obtained from 74% of patients. KRAS mutation analysis in CTC-enriched specimens showed that 45% and 16.7% of patients with mutant and wild type primary tumors, respectively, had detectable mutations in their CTCs. Assessing KRAS mutations in serial blood samples revealed that individual patient's CTCs exhibited different mutational status of KRAS during treatment. CONCLUSIONS: The current findings support the rationale for using the CTCs as a dynamic source of tumor cells which, by re-evaluating their KRAS mutation status, could predict, perhaps more accurately, the response of mCRC patients to targeted therapy.

Combined analysis of KRAS and PIK3CA mutations, MET and PTEN expression in primary tumors and corresponding metastases in colorectal cancer.

Metastasis is the main cause of mortality in patients with colorectal cancer. However, most of the targeted therapies and predictive molecular biomarkers were developed based mainly on primary tumors. The current study was conducted to determine the degree of discordance between potential predictive and/or prognostic molecular markers in primary colorectal tumors and corresponding metastases, as this could have an impact on the efficacy of targeted therapies in the advanced colorectal cancer. KRAS, PIK3CA and BRAF mutations were determined by Sanger sequencing and mutant-enriched polymerase chain reaction (PCR) assays in 83 paired samples, MET gene copy number by quantitative PCR in 59, MET expression by immunohistochemistry in 73 and nuclear and cytoplasmic expression of PTEN by immunohistochemistry in 78 and 71 pairs, respectively. A certain degree of discordance between primary tumors and corresponding metastases was demonstrated for all examined biomarkers except BRAF mutations. PIK3CA exon 9 mutations in primary tumors and loss of PTEN nuclear expression in metastases correlated with KRAS mutations. KRAS wild-type status in primary tumors was associated with loss of PTEN cytoplasmic expression and high gene copy number of MET. Survival and clinical data were available for 68 patients. The multiple regression analysis revealed that the right-sided tumor localization and overexpression of MET were associated with shorter overall survival.

Impact of KRAS, BRAF, PIK3CA mutations, PTEN, AREG, EREG expression and skin rash in ≥ 2 line cetuximab-based therapy of colorectal cancer patients.

BACKGROUND: To investigate the predictive significance of KRAS, BRAF, PIK3CA mutational status, AREG- EREG mRNA expression, PTEN protein expression and skin rash in metastatic colorectal cancer (mCRC) patients treated with cetuximab containing salvage chemotherapy. METHODS: Primary tumors from 112 mCRC patients were analyzed. The worst skin toxicity during treatment was recorded. RESULTS: KRAS, BRAF and PIK3CA mutations were present in 37 (33%), 8 (7.2%) and 11 (9.8%) cases, respectively, PTEN was lost in 21 (19.8%) cases, AREG and EREG were overexpressed in 48 (45%) and 51 (49%) cases. In the whole study population, time to tumor progression (TTP) and overall survival (OS) was significantly lower in patients with KRAS (p = 0.001 and p = 0.026, respectively) or BRAF (p = 0.001 and p<0.0001, respectively) mutant tumors, downregulation of AREG (p = 0.018 and p = 0.013, respectively) or EREG (p = 0.002 and p = 0.004, respectively) and grade 0-1 skin rash (p<0.0001 and p<0.0001, respectively). In KRAS wt patients TTP and OS was significantly lower in patients with BRAF (p = 0.0001 and p<0.0001, respectively) mutant tumors, downregulation of AREG (p = 0.021 and p = 0.004, respectively) or EREG (p = 0.0001 and p<0.0001, respectively) and grade 0-1 skin rash (p<0.0001 and p<0.0001, respectively). TTP was significantly lower in patients with PIK3CA mutations (p = 0.01) or lost PTEN (p = 0.002). Multivariate analysis revealed KRAS (Hazard Ratio [HR] 4.3, p<0.0001), BRAF mutation (HR: 5.1, p<0.0001), EREG low expression (HR: 1.6, p = 0.021) and absence of severe/moderate skin rash (HR: 4.0, p<0.0001) as independent prognostic factors for decreased TTP. Similarly, KRAS (HR 2.9, p = 0.01), BRAF mutation (HR: 3.0, p = 0.001), EREG low expression (HR: 1.7, p = 0.021), absence of severe/moderate skin rash (HR: 3.7, p<0.0001) and the presence of undifferantited tumours (HR: 2.2, p = 0.001) were revealed as independent prognostic factors for decreased OS. CONCLUSIONS: These results underscore that KRAS-BRAF mutations and EREG expression can be used as biomarkers to further select patients undergoing anti-EGFR treatment.

Clinical outcome of patients with non-small cell lung cancer receiving front-line chemotherapy according to EGFR and K-RAS mutation status.

BACKGROUND: Somatic mutations in EGFR and K-RAS may predict for sensitivity and resistance to EGFR tyrosine kinase inhibitors (TKIs). Whether EGFR and K-RAS mutations could also predict clinical outcome of non-small cell lung cancer (NSCLC) patients following front-line chemotherapy has not yet been established. PATIENTS AND METHODS: One hundred and sixty-two chemotherapy-naïve patients with locally advanced/metastatic NSCLC who received front-line chemotherapy were included in this retrospective study and their clinical outcome data was analyzed according to EGFR and K-RAS mutation status of their tumors. RESULTS: Classical activating EGFR and K-RAS mutations were found in 8.2 and 22.6% of patients respectively and were not associated with patients' clinicopathological characteristics. Patients with classical EGFR mutations had a higher probability of response to front-line chemotherapy as compared to those with wild type EGFR (p=0.023). Multivariate analysis showed that the presence of activating EGFR mutations was an independent factor associated with response to front-line chemotherapy (HR=4.85; 95% CI: 1.13-20.83, p=0.034). K-RAS mutation status was not associated with response to front-line chemotherapy. The presence of activating EGFR but not of K-RAS mutations was associated with a significantly higher overall survival compared to patients without mutations treated with platinum-based front-line chemotherapy (p=0.043). CONCLUSIONS: The data indicate that EGFR mutation status could be predictive for response to cytotoxic front-line chemotherapy in patients with NSCLC. Additional prospective studies are needed in order to validate this observation and to define whether these patients should be preferentially treated with front-line TKIs or chemotherapy.

DNA repair gene polymorphisms predict favorable clinical outcome in advanced non-small-cell lung cancer.

BACKGROUND: Genetic polymorphisms of genes involved in DNA repair and glutathione metabolic pathways may affect patients' response to platinum-based chemotherapy. We retrospectively assessed whether single nucleotide polymorphisms (SNP) of DNA-repair genes ERCC1, XPD, XRCC1 and glutathione S-transferase genes GSTP1, GSTT1 and GSTM1 predict overall survival (OS), response and toxicity in 119 non-small-cell lung cancer (NSCLC) patients treated with platinum-based regimens as first- or second-line chemotherapy. PATIENTS AND METHODS: Patients' genotypes were determined by PCR-RFLP and sequencing approaches. RESULTS: ERCC1 (Asn118Asn) genotype was significantly associated with response to treatment. Patients with either one or two C alleles (C/C, C/T) at Asn118Asn were more likely to respond to platinum-based chemotherapy compared with those without the C allele (Odds ratio, 0.10; 95% CI, 0.013-0.828; P = .033, by binary logistic regression). There was a significant association between the ERCC1 C8092A polymorphism and OS (P = .009, by log-rank test), with median survival times of 9.8 (C/C) and 14.1 (C/A or A/A) months, respectively, suggesting that any copies of the A allele were associated with an improved outcome. Cox's multivariate analysis suggested that the joint effect of ERCC1 polymorphic variants (C8092A and N118N) (0 vs. 2, hazard ratio 2.5; 95% CI, 1.26-4.96; P = .009) as well as the XRCC1 N399Q polymorphism (AA vs. GA/GG, hazard ratio 3.1; 95% CI, 1.4-6.8; P = .005) were independent prognostic factors for OS in advanced NSCLC patients treated with platinum-based chemotherapy. CONCLUSION: These findings support the notion that assessment of genetic variations of ERCC1 and XRCC1 could facilitate therapeutic decisions for individualized therapy in advanced NSCLC.