Abstract
Purpose:
Oncogenic mutations for PIK3CA, RAS (KRAS, NRAS), BRAF and MET have been identified in various malignancies, and activate the PI3K/ AKT/mTOR and RAS/RAF/MEK pathways respectively. Both pathways are critical drivers of tumorigenesis.
Methods:
Tumor tissue from 21 patients with lacrimal gland epithelial neoplasms (3 benign pleomorphic adenomas and 18 malignant: 14 adenoid cystic carcinomas, 2 low grade myoepithelial carcinoma-ex pleomorphic adenomas, one high grade salivary duct-like carcinoma-ex pleomorphic adenoma, one squamous carcinoma) treated at M. D. Anderson Cancer Center were analyzed for PIK3CA, RAS (KRAS, NRAS), BRAF and MET using polymerase chain-reaction based DNA sequencing.
Results:
KRAS mutations were found in 10 (48 %) of 21 patients tested; NRAS in 2 (10 %); MET in 3 (14%) of 21 patients tested; PIK3CA in 1 (5 %) of 21 patients tested; BRAF in 0 of 21 patients tested. Half of oncogenic mutations were found in adenoid cystic carcinoma (8/14, 57%). KRAS mutations were most frequent in adenoid cystic carcinoma (5/10, 50%), as well as MET mutations (2/3, 67%), NRAS mutations (1/2, 50%) and none for PIK3CA/ BRAF. In one benign mixed tumor KRAS mutations coexisted with NRAS and PIK3CA; in another benign mixed tumor both KRAS and NRAS mutations were found. One high grade carcinoma was found to have concurrent KRAS and MET mutations.
Conclusions:
RAS (KRAS, NRAS), PIK3CA and MET mutations are frequent in diverse epithelial neoplasms of lacrimal gland with the highest proportion of mutations found in adenoid cystic carcinoma. PIK3CA and MET mutations can coexist with RAS mutations.
Keywords: 631 orbit •
624 oncology •
604 mutations