Introduction

EGFR mutations, del E746-A750 in exon 19 and L858R in exon 21 in tumor cells of NMLC represent biomarkers of response to tyrosine kinase inhibitors (TKI) therapy. Patients with tumors positive for EGFR mutations show better response and greater survival. These mutations occupy 90% of mutations in lung cancer.

Objective

To evaluate the frequency of mutations del E746-A750-exon 19 and L858R-exon 21 of EGFR gene in NMLC biopsy samples and in serum samples of the general population from Yucatán.

Material and methods

19 NMLC biopsy samples of adenocarcinoma type and 101 serum samples from healthy subjects were selected. EGFR mutations del E746-A750 and L858R were determined by allele-specific PCR amplification (PCR-ASO). The genotypic and allelic frequencies; and their distribution according to Hardy Weinberg expectations were calculated using the SNPstats software.

Results

For serum, EGFR del E746-A750 mutation, homozygous genotype (1/1) was present in 26.58%, heterozygote (1/0) in 73.42% and absence of mutant genotype with deletion (0/0); whereas for L858R mutation, 21.78% were homozygous (TT), 54.46% heterozygous (T/G) and 23.76% GG mutants. For the NMLC biopsies, the heterozygote was the most frequent genotype for both mutations, 63.16% and 73.68% for del E746-A750 and L858R, respectively.

Conclusion

The frequency of mutations of EGFR gene in serum samples was 36.71% for deletion delE746-A750 in exon 19 and 50.99% for L858R in exon 21. Distribution of mutations in biopsy samples NMLC resulted in 42.11% for each EGFR mutation.