WTBZ]Survivin belongs to the member of IAP family (inhibitor of apoptosis, IAP) proteins and is a bifunctional protein that suppresses apoptosis and regulates cell division. Survivin is a tumor specific antiapoptosis factor that is expressed selectively in all the most common human carcinomas but not in normal adult tissues. Studies indicated that Survivin played a crucial role in the genesis and progression of malignancy and was an important predictive/prognostic parameter in tumors. Survivin also participates in angiogenesis. Recently, Survivin has been used as a novel diagnostic/therapeutic target in cancer.

The characteristic genetic abnormality of neuroendocrine neoplasms (NENs), a heterogeneous group of tumors found in various organs, remains to be identified. Here, based on the analysis of the splicing variants of an oncogene Focal Adhesion Kinase (FAK) in The Cancer Genome Atlas datasets that contain 9193 patients of 33 cancer subtypes, we found that Box 6/Box 7-containing FAK variants (FAK^6/7) were observed in 7 (87.5%) of 8 pancreatic neuroendocrine carcinomas and 20 (11.76%) of 170 pancreatic ductal adenocarcinomas (PDACs). We tested FAK variants in 157 tumor samples collected from Chinese patients with pancreatic tumors, and found that FAK^6/7 was positive in 34 (75.6%) of 45 pancreatic NENs, 19 (47.5%) of 40 pancreatic solid pseudopapillary neoplasms, and 2 (2.9%) of 69 PDACs. We further tested FAK splicing variants in breast neuroendocrine carcinoma (BrNECs), and found that FAK^6/7 was positive in 14 (93.3%) of 15 BrNECs but 0 in 23 non-NEC breast cancers. We explored the underlying mechanisms and found that a splicing factor serine/arginine repetitive matrix protein 4 (SRRM4) was overexpressed in FAK^6/7-positive pancreatic tumors and breast tumors, which promoted the formation of FAK^6/7 in cells. These results suggested that FAK^6/7 could be a biomarker of NENs and represent a potential therapeutic target for these orphan diseases.
Female ; Humans ; Alternative Splicing ; Breast Neoplasms/metabolism* ; Carcinoma, Pancreatic Ductal/pathology* ; Focal Adhesion Protein-Tyrosine Kinases/therapeutic use* ; Nerve Tissue Proteins/genetics* ; Neuroendocrine Tumors/genetics* ; Oncogenes ; Pancreatic Neoplasms/metabolism*