The anaplastic lymphoma kinase (ALK) rearrangement is responsible for about 4-7% of all non-small cell lung cancers (NSCLCs) and perhaps as high as a third in specific patient populations such as younger, male, non-smokers with advanced stage, epidermal growth factor receptor (EGFR) and Kirsten rat sarcoma viral oncogene (KRAS) wild type, and signet ring cell adenocarcinoma with abundant intracytoplasmic mucin.
ALK-positive pulmonary adenocarcinoma exhibits characteristic histological features, such as signet ring cell carcinoma (SRCC) and a mucinous cribriform structure.
The expression of ALK protein was first determined in paraffin-embedded tissue specimens (FFPE) from 177 pathologically confirmed SRC patients by Ventana Immunohistochemistry (IHC).