Anaplastic lymphoma kinase (ALK) gene alteration in gastric signet ring cell carcinoma

This study was aimed to investigating the frequency of Anaplastic lymphoma kinase (ALK) alterations in patients with gastric signet ring cell carcinoma (SRC) and the correlations between ALK alterations and the clinical-pathological features.The expression of ALK protein was first determined in paraffin-embedded tissue specimens (FFPE) from 177 pathologically confirmed SRC patients by Ventana Immunohistochemistry (IHC). Then patients with ALK positive detected by IHC were assayed in ALK rearrangement by Fluorescence in Situ Hybridization (FISH).We assessed 4 of 177 cases (2.3%) as positive by IHC. 3 of the 4 patients had T4 tumors and positive nodal status, and 1 of them had metastasis. All of them were HER2 negative. All of the 4 patients were positive for ALK rearrangement using the standard criteria of FISH.Our analysis showed that about 2.3% of Chineses SRC patients treated in our hospital were ALK positive. Ventana IHC and FISH were both of the reliable approaches in SRC patients. Patients with ALK positive seemed to have deep infiltrated and positive lymph nodes and HER2 negative.