Prevalence and effect of PIK3CA H1047R somatic mutation among Indian head and neck cancer patients.

ABSTRACT

PIK3CA is one among the several mutated genes in cancer, including head and neck squamous cell carcinoma (HNSCC). H1047R is a hotspot somatic mutation in PIK3CA that occurs most frequently in several forms of cancers. Distribution of PIK3CA H1047R mutation in Indian HNSCC patients was screened and its effect on disease progression and response to treatment was analysed in this study. Genomic DNA was extracted from tumour biopsies of HNSCC patients (n = 48) and polymerase chain reaction coupled restriction fragment length polymorphism (PCR-RFLP) technique was used to screen for the mutation. Overall survival (OS) and Progression-free survival (PFS) of the patients were calculated in order to study effect of this mutation on survival and response to treatment respectively. Results showed that irrespective of patients' criteria, twenty-five patients (52 %) carried a heterozygous form of mutation (His/Arg) and the rest (48 %) were wild type (His/His). The mean OS of the cohort with the mutation was 20.451 months (SE ± 1.710 months) while 26.31 months (SE ± 2.431) was in wild type population. PFS of the patients with the mutation was 18.612 months (SE ± 2.072), and for the wild type population, it was 26.31 months (SE ± 2.431). These observations suggest that Indian HNSCC patients with PIK3CA H1047R mutation have poor prognosis.