ABSTRACT
BACKGROUND: One of the genetic alterations implicated in tumor progression in colorectal cancers (CRCs) are abnormalities in Kristen Rat Sarcoma (KRAS) gene. Evaluation of KRAS mutation status is an important prognostic factor and has predictive value in deciding first line therapy based on monoclonal antibodies such as Cetuximab and Panitumumab in metastatic CRCs. MATERIALS AND METHODS: In this retrospective study, we analyzed 7 different somatic mutations in Exon 2 of KRAS gene in 299 unselected incidental CRC patients who visited the hospital for clinical management during the period 2009–2013. Most of the tumors were primarily originating from colon and rectum; nevertheless, there were a few from rectosigmoid, sigmoid, ceacum and anal canal in the study group. Genomic DNA extracted from paraffin embedded tumor tissues was screened for 7 point mutations located in Codons 12 and 13 of KRAS gene, using Scorpions amplified refractory mutation system real time polymerase chain reaction technology. Statistical analysis was performed to assess bivariate relationship between different variables that includes: mutation status, mutation type, tumor location, tumor morphology, age and sex. RESULTS: Prevalence of mutation in Codons 12 and 13 was 42.8% in the study group. Well‑differentiated tumors had significantly more mutation positivity than moderately and poorly differentiated tumors (P = 0.001). 92% of the mutations were from Codon 12 and 8% in Codon 13. Glycine to Arginine was relatively more common in rectosigmoid followed by ceacum, while Glycine to Alanine mutation was relatively more prevalent in sigmoid, followed by rectum and rectosigmoid. CONCLUSION: The results suggest a prevalence of KRAS mutation at 42.8% in Indian population indicating that this testing is very crucial for targeted therapy management in metastatic CRC in India. Further analysis on mutation status of other homologues such as NRAS and downstream partner, v‑raf murine sarcoma viral oncogene homolog B1, would add value to understanding the role of anti‑epidermal growth factor receptor therapy in CRC management.
ABSTRACT
BACKGROUND: Epidermal growth factor receptor (EGFR) mutation plays a vital role in the prognosis of patients with lung cancer. However, there is a dearth of studies on EGFR mutation in Indian population. In this retrospective study conducted at a network of tertiary cancer care centers across India, we evaluated the proportion of EGFR mutation in patients with non‑small‑cell lung carcinomas (NSCLC). MATERIALS AND METHODS: A total of 1036 cases of non‑small lung cancer were assessed for EGFR mutation status using Scorpion amplified refractory mutation system real time polymerase chain reaction method from fine needle aspiration cytology core biopsy, pleural fluid and cell blocks. For a few cases, macro dissection of tumor from H and E slides was also performed for EGFR analysis. EGFR Status was assessed for the most commonly known driver mutations in Exons 18, 19, 20 and 21, which contributes to a total of 29 somatic mutations including the resistance mutation T790M. RESULTS: Around 39% of the cohort was female and 61% were male. Mutation was positive in 40.3% and negative (wild type) in 59.7%. There was 1.8% mutation in exon 18, 24.6% in exon 19, 1.6% in exon 20 and 12.8% in exon 21. 38.2% had a mutation in a single site and 1.1% had a mutation in two sites. Overall mutation was significant in females (50.5% vs. 33.9%) compared with males (c2 = 28.3, P < 0.001). Mutation was significant in exon 21 (16.8% vs. 10.3%, c2 = 9.44, P = 0.002) and exon 19 (30.7% vs. 20.7%, c2 = 13.2, P < 0.001) in females compared with males. CONCLUSION: EGFR is expressed differentially/ mutated in patients with NSCLC. Further studies to unravel the predictors for acquired genetic alterations of EGFR are needed.