PIK3CA and adenocarcinoma: Interestingly, although some alterations such as ERBB2 and MET amplifications are only seen in adenocarcinomas (both intestinal and signet-cell carcinoma, and in both gastric and oesophageal tumors), EGFR and CCND1 amplifications and PIK3CA alterations were found in patients with both adenocarcinoma and squamous cell histologies.