Prognostic significance of prostaglandin E2 production by mononuclear cells and tumor cells in squamous cell carcinomas of the head and neck.

Prostaglandin E2 (PGE2) has been implicated as a cause of immunosuppression in patients with head and neck cancer. To determine the relative contribution of tumor cells and mononuclear cells to PGE2 levels in vivo, tumor cells and tumor-infiltrating mononuclear cells (TIMC) were isolated from fresh tumor biopsy specimens of 23 patients with squamous cell carcinoma of the head and neck (SCCHN) by using enzymatic digestion and differential gradient centrifugation. Peripheral blood mononuclear cells (PBMC) and lymph node mononuclear cells (LNMC) from metastatic and nonmetastatic lymph nodes were also isolated. Cell fractions were cultured for 24 hours, and PGE2 levels of supernatant were determined by radioimmunoassay. PGE2 production by LNMC was significantly decreased compared to tumor cells, TIMC, and PBMC (P = .0002). LNMC from metastatic lymph nodes produced significantly higher levels of PGE2 (P = .02) compared to nonmetastatic lymph nodes. Although T stage was not correlated with PGE2 production by TIMC or tumor cells, advanced N stage (N1-3) was associated with decreased PGE2 production by TIMC (P = .006). These results suggest that both tumor cells and TIMC are sources of PGE2 in tumor tissues of patients with SCCHN and that decreased PGE2 production by host inflammatory cells may have clinical significance in the development of cervical metastases.