Epidermal growth factor receptor mutation subtypes and geographical distribution among Indian non-small cell lung cancer patients.

BACKGROUND

The Medical Oncology Department at Tata Memorial Hospital, the single largest tertiary cancer care center in Asia, receives in-house registered and referral patient samples from all parts of the country. Our recent studies establish 23% EGFR mutation frequency among Indian population. Here, we extend our study and report further analysis of distribution of different types of EGFR mutations in 1018 non small cell lung cancer patient, and its co-relation with clinical parameters and geographical variations across the country.

MATERIAL AND METHODS

This study is a retrospective analysis on all the patients who were referred for EFGR testing as a routine service over a 1.5 year period. This was part of standard care. EGFR kinase domain mutations in exon 18-21 were probed by TaqMan probe-based assays in 1018 NSCLC patients.

RESULTS AND DISCUSSION

While EGFR exon 19 mutations, the most frequent EGFR mutation, were found be higher among non smokers females, we find surprisingly higher incidence of exon 21 mutations among EGFR mutation positive male smokers of Indian ethnicity. Furthermore, as Indian population is known to be composed of a gradient admixture of Ancestral North Indian (with genetic influence from Middle Easterners, Central Asians, and Europeans harboring variant EGFR mutation frequency) and Ancestral South Indians, as a paradox our study indicates comparable EGFR mutation frequency across different geographical locations within India

CONCLUSION

Geographically there is uniform distribution in the EGFR mutation frequency within India. Further more, while exon 19 mutations are predominant among non smokers, higher incidence of exon 21 mutations exists among EGFR mutation positive male smokers of Indian ethnicity.