This study was aimed to test whether PIK3CA, BRAF and RAS are mutated in nasopharyngeal carcinomas (NPCs) and, if so, to further determine whether such mutations affect patients’ survival. For this purpose, a total of 73 NPCs were subjected to mutational analyses for PIK3CA (exons 4, 7, 9, and 20), BRAF (codon 600), and RAS (codons 12, 13 and 61). Clinicopathological characteristics were correlated to the mutation data. Survival rates were compared with the log-rank test. The result showed that the mutation rate of PIK3CA in NPC (n = 73) was 9.6%, whereas both BRAF (n = 65) and RAS (n = 45) were wild type in every specimen with adequate DNA for analysis. PIK3CA mutation was slightly influenced by sex (P = 0.0418, Fisher’s exact test), but had no significant relationship to other clinicopathological characteristics. Disease-specific survival was not significantly affected by PIK3CA mutations (P = 0.8825, log-rank test), albeit it was slightly better in younger patients (≤35 vs. >35 years of age) (P = 0.0477). These findings show that mutated PI3K may be involved in the NPC tumorigenesis but does not affect patient’s prognosis, suggesting that PI3K is a potential target in NPC for targeted therapeutics using specific kinase inhibitors.
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This work was supported in part by NSC 95-2320-B-195-001 from National Science Council, Taiwan, and MMH-E-96002 from Mackay Memorial Hospital, Taipei, Taiwan.
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