Epidermal growth factor receptor (<it>EGFR</it>) mutations and expression in squamous cell carcinoma of the esophagus in central Asia

<p>Abstract</p> <p>Background</p> <p>Esophageal squamous cell carcinoma (ESCC) shows geographic variations in incidence, with high incidences (>50/10⁵ person-years) in central Asia, including North Eastern Iran (Golestan) and Northern India (Kashmir). In contrast to Western countries, smoking does not appear to be a significant risk factor for ESCC in central Asia. In lung adenocarcinoma, activating mutations in the gene encoding epidermal growth factor receptor (<it>EGFR</it>) are frequent in tumors of never smokers of Asian origin, predicting therapeutic sensitivity to <it>Egfr</it>-targeting drugs.</p> <p>Methods</p> <p>In this study 152 cases of histologically confirmed ESCC from Iran (Tehran and Golestan Province) and North India (Kashmir Valley) have been analyzed for <it>EGFR</it> mutation by direct sequencing of exons 18–21. <it>Egfr</it> protein expression was evaluated by immunohistochemistry in 34 samples from Tehran and <it>HER2</it> mutations were analyzed in 54 cases from Kashmir.</p> <p>Results</p> <p>A total of 14 (9.2%) <it>EGFR</it> variations were detected, including seven variations in exons. Among those, four (2.6%) were already documented in lung cancers, two were reported as polymorphisms and one was a potentially new activating mutation. All but one variation in introns were previously identified as polymorphisms. Over-expression of <it>Egfr</it> was detected in 22/34 (65%) of tested cases whereas no <it>HER2</it> mutation was found in 54 cases from Kashmir.</p> <p>Conclusion</p> <p>Overall, <it>EGFR</it> mutations appear to be a rare event in ESCC in high incidence areas of central Asia, although a very small proportion of cases may harbor mutations predicting sensitivity to anti-<it>Egfr</it> drugs.</p