PIK3CA and nasopharyngeal carcinoma: And base on these indicators were used as positive control, the current study showed that in nasopharyngeal carcinoma patients that treated with cetuximab, those with KLF4 expression in the nucleus showed a poor prognosis, and the KLF4 expression in the nucleus was significantly associated with common drug resistance-related indicators such as H-Ras and PI3K mutations.