Multivariate Cox regression analysis of clinical variables on overall survival accord to (A) PIK3CA mutation status and (B) PIK3CA expression status.

a<p>Adjust by age, gender, tobacco use, alcohol use, family cancer history, tumor location, pathologic T classification, degree of differentiation, lymph node metastasis, tumor embolus and local recurrence.</p>b<p>Adjust by gender, tobacco use, alcohol use, family cancer history, tumor location, pathologic T classification, degree of differentiation, lymph node metastasis, tumor embolus and local recurrence.</p>c<p>Adjust by age, gender, tobacco use, alcohol use, tumor location, pathologic T classification, degree of differentiation, lymph node metastasis, tumor embolus and local recurrence.</p>d<p>Adjust by age, tobacco use, alcohol use, family cancer history, tumor location, pathologic T classification, degree of differentiation, lymph node metastasis, tumor embolus and local recurrence.</p>e<p>Adjust by age, gender, alcohol use, family cancer history, tumor location, pathologic T classification, degree of differentiation, lymph node metastasis, tumor embolus and local recurrence.