PIK3CA and squamous cell carcinoma: We performed a retrospective study investigating the frequency of TP53 and PIK3CA mutations in pre-treatment biopsies from a cohort of patients with mucinous and non-mucinous adenocarcinoma, squamous cell carcinoma and CIN 3 and we correlated the TP53 and PIK3CA mutational status with histological subtypes and HPV status.