Salivary
adenoid cystic carcinoma is one of the most common
malignancies of the head and neck. The lysosome-associated
protein transmembrane-4β gene (LAPTM4B) is a novel oncogene that has been found overexpressed in a number of clinically aggressive
cancers. This study aimed to investigate the expression of the LAPTM4B-35
protein in normal salivary gland and salivary
adenoid cystic carcinoma, a relatively indolent
malignancy, and explore its clinicopathological significance in this
malignancy. By immunohistochemical analysis, LAPTM4B-35 expression was evaluated in 106
cancer tissues, their adjacent non-cancerous tissues and five normal salivary glands. The correlation of LAPTM4B-35 expression with clinicopathological parameters was assessed using Chi-square or Fisher's exact test. The level of LAPTM4B-35 expression varied among different cell types of normal salivary glands. It was expressed at a fairly low level in serous and mucous acini, at low level in intercalated duct and excretory duct cells and moderately in secretory/striated ducts. In 50% of high grade
tumor tissues tested, LAPTM4B-35 was markedly overexpressed. LAPTM4B-35 levels were significantly associated with histological grade and clinical stage. LAPTM4B-35 plays an important role in salivary
adenoid cystic carcinoma and may serve as a diagnostic marker and a target for individualized
therapy.