Clinically relevant tumors with near complete absence of PAX8 staining (< 1%) included for example all subtypes of breast cancers, gastric adenocarcinoma, prostatic adenocarcinoma, hepatocellular carcinomas, cholangiocarcinoma, gallbladder adenocarcinoma, pulmonary adenocarcinoma, neuroendocrine neoplasms, and small cell carcinomas of various sites. This evidence concerns the gene PAX8 and small cell carcinoma.