Affiliations: [a] Department of Internal Medicine, King Fahd Hospital of the University, University of Dammam, Al-Khobar, Kingdom of Saudi Arabia | [b] Institute for Research & Medical Consultation, University of Dammam, Dammam, Kingdom of Saudi Arabia | [c] Department of Pathology, King Fahd Hospital of the University, University of Dammam, Al-Khobar, Kingdom of Saudi Arabia | [d] Department of Microbiology, University of Dammam, Dammam, Kingdom of Saudi Arabia
Correspondence:
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Corresponding author: Chittibabu Vatte, Institute for Research & Medical Consultation, University of Dammam, Dammam, Kingdom of Saudi Arabia. E-mail:cbvatte@uod.edu.sa
Abstract: BACKGROUND: HNSCC is the sixth most common human cancer globally.
In Saudi Arabia, HNSCC accounts for seven percent of all newly diagnosed
cancer cases. The PIK3CA is one of the most commonly mutated oncogene in
human malignancies, including HNSCC. OBJECTIVE: The objective of
this study is to identify mutations in exon 9 and exon 20 of the PIK3CA gene
among Saudi HNSCC patients, determine the frequency of these mutations and
correlate with clinical and pathological findings. METHODS: Histopathologically confirmed paraffin embedded HNSCC tumor tissues from 48
patients were obtained. Capillary sequencing method was used to sequence
exons 9 and 20 of the PIK3CA gene. Concurrently, the expression analysis of
the PIK3CA and PTEN genes were performed using real-time PCR. RESULTS: Sixty percent of the samples studied were of pharyngeal cancer. A
total of seven mutations were identified in exons 9 and 20 of the PIK3CA
gene in 14 HNSCC tumor tissue specimens. The seven mutations encompassed one
hot spot mutation E542K, a common mutation T1025T and the five novel
mutation comprising three missense and two silent mutations. Interestingly,
eight out of the 14 samples with a mutation were of patients with pharyngeal
cancer. CONCLUSION: PIK3CA gene plays a crucial role in
carcinogenesis in general and HNSCC in particular. The identification of
five novel mutations suggest that Saudis may have different frequencies of
somatic genetic alterations that may influence HNSCC compared to other
populations.
