Figure 1: IHC and FISH for ALK in cytological specimens of lung adenocarcinoma. Cell block of pleural fluid with metastatic lung adenocarcinoma from an elderly woman. The tumour cells were negative for ALK IHC (A) low power and (B) high power. (C) FISH using a break apart probe was negative for ALK gene rearrangement with two fused red/green signals. Cell block from a fine needle biopsy of metastatic lung adenocarcinoma in a cervical lymph node from a 34 year old woman. The tumour cells were positive for ALK IHC (D) low power, (E) high power. (F) FISH showed ALK gene rearrangement with split red and green signals.