Lack of Mutations in Protein Tyrosine Kinase Domain Coding Exons 19 and 21 of the EGFR Gene in Oral Squamous Cell Carcinomas

Abstract

<b>Background:</b> The epidermal growth factor receptor (EGFR) plays a vital role in the activation and inactivationof receptor tyrosine kinases. Mutations in exons 19 and 21 of EGFR are commonly found to be associatedwith non small cell lung carcinoma and triple negative breast cancer, enhancing sensitivity to EGFR targetingchemotherapeutic agents. Since amplification and prolonged activation of EGFR molecules have been identifiedin oral squamous cell carcinomas (OSCC), we investigated whether OSCCs carried mutations in exons 19 and21 of EGFR to their incidence. Materials and <br/><b>Methods</b>: Tumor chromosomal DNA isolated from forty surgicallyexcised oral squamous cell carcinoma tissues was subjected to PCR amplification with intronic primers flankingexons 19 and 21 of the EGFR gene. The PCR amplicons were subsequently subjected to direct sequencing toelucidate the mutation status. <br/><b>Results</b>: Data analysis of the EGFR exon 19 and 21 coding sequences did not showany mutations in the forty OSCC samples that were analyzed. <br/><b>Conclusions</b>: To the best of our knowledge, this isthe first study to have investigated the genetic status of exons 19 and 21 of EGFR in Indian OSCCs and identifiedthat mutation in EGFR exon 19 and 21 may not contribute towards their genesis. The absence of mutationsalso indicates that oral cancerous lesions may not be as sensitive as other cancers to chemotherapeutic agentstargeting EGFR.