Cytomegalovirus induces Interleukin-6 mediated inflammatory response in salivary gland cancer

The purpose of this study was to examine whether cytomegalovirus (CMV) is present in different histological types of salivary gland cancer (SGC) by detecting CMV immediate-early (IE) and early gene products, and to determine the presence of its association with the overexpression of interleukin (IL)-6.

Immunohistochemical analysis of 92 cases of different histological types of SGC was performed to determine the presence of IL-6 and CMV antigen and its intensity in tumor tissue. Twenty samples of normal salivary gland tissue obtained during autopsy served as healthy controls.

CMV antigens were not found in healthy acinar tissue of salivary glands, but were expressed in epithelium of salivary gland ducts. Negative expression of CMV antigens was also found in salivary gland tissue surrounding tumors. On the other hand, CMV was detected in 65/92 SGC cases (70.6%). Higher expression of IL-6 was found in SGC (70.7%) than in normal tissue (20%). There was a high association of CMV antigen presence with the presence of IL-6, and with the IL-6 expression intensity.

Positive expression of CMV antigens in a high percentage of SGC cells suggests that it might play an important role in carcinogenesis by increasing IL-6 production and leading to inhibition of apoptosis and tumor development.