Reclassifying bronchial-pulmonary carcinoma: differentiating histological type in biopsies by immunohistochemistry.

The current state of molecular knowledge on lung cancer demands a histological classification which goes beyond small-cell and non-small-cell carcinoma to provide support for tailored therapy in aiding in understanding of the drugs currently available. As diagnosis and follow-up in the vast majority of lung cancer cases is based on biopsies and cytology samples, Immunohistochemical Bronchial Pulmonary Carcinoma Classification (IBPCC) is necessary to reveal the raft of characteristics available. This provides morphological support for the WHO's 1999/2004 classification, in addition to an understanding of carcinogenesis. The immunohistochemical panel clarifies the main morphology and cytology characteristics to maintain the leading histological types as squamous cell carcinoma (high weight molecular cytokeratins/HWMC), adenosquamous carcinoma (CK7, TTF1, HWMA), neuroendocrine carcinoma (Chrg, Syn, CD56, TTF1, Ki67), adenocarcinoma (CK7, CK20, TTF1) and bring the polymorphic and pleomorphic carcinomas under a single banner of pleomorphic carcinoma (Ck7, TTF1, HWMC, VMT, Desmin, Actin) which shelters large cell carcinomas and sarcomatoid carcinomas. Lung cancer chemotherapy will still be based on platinum and gemcitabine for the near future and the IBPCC is a simple and efficient tool for streamlining the registration of lung cancer histological characteristics in biopsies and other reduced samples to support clinical evidence and trials.