The host immune system normally functions to destroy neoplastic cells that continually develop as a result of somatic mutations. However, patients with head and neck squamous cell carcinoma have depressed cell-mediated immune function, which has recently been shown to be most pronounced in the local and regional environment of the primary tumor. Recent studies suggest a local modulation of the host immune response to tumor by secreted immunoregulatory factors such as cytokines, especially pro-inflammatory cytokines(interleukin-1, interleukin-6, interleukin-8, interferons, and tumor necrosis factor).

To assessthe ability of head and neck squamous cell carcinoma to produce these cytokines, initially, we have performed immunohistochemical staing for interleukin-6 and tumor necrosis factor in 20 cases of laryngeal squamous cell carcinoma and 10 cases of laryngeal nodule as a control group.

We detected interleukin-6 in 11 cases of laryngeal squamous cell carcinoma(55%) and tumor necrosis factor in 11 cases of laryngeal squamous cell carcinoma(55%). All of 10 papillomas showed no expression of interleukin-6 and tumor necrosis factor. There is no statistical correlation between interleukin-6 and tumor necrosis factor expression and clinical stage or pathologic grade.

These results suggest that laryngeal squamous cell carcinoma may secrete cytokines influencing the response of local immune cells. But future studies of the role of tumorderived cytokines in the local immune response to tumor could be investigated,since cytokines may directly or indirectly regulate tumor growth and metastasis.

Various mechanisms are involved in drug resistance of tumor cells. Among them one such mechanism is the overexpression of the multidrug resistance(mdr1) gene product P-glycoprotein(Pgp) that functions as an energy - dependent drug efflux pump.

The expression of P-glycoprotein by immunohistochemistry was examined in 20 cases of laryngeal squamous cell carcinoma and vocal nodules as a control pump using a newly developed monoclonal antibody(MDR/JSB-1) which is specipic to human mdr1 gene product and recognizes an external epitope of the protein. Mdr1 gene product expression was compared with clinical response to chemotherapy in six patients who received mdr1 dependent drugs.

The results are summerized as follows.

1) Among 20 laryngeal cancer tissues, P-glycoprotein was detected in 8 patients and none of 20 vocal nodules showed expression of P-glycoprotein.

2) There is a correlation in between positive P-glycoprotein staining and tumor differentiation.

3) No correlation in between positive P-glycoprotein standing and tumor stage of tumor site is observed.

4) 2 patients with negative clinical response to chemotherapy among 6 patients who received inductive chemotherapy with cisplatin, vincristine and p pepleomycin revealed positive P-glycoprotein staining.

Therefore, analyzing the expression of P-glycoprotein may play a role when planning chemotherapeutic regimens for patients with head and neck cancer and may be an additional prognostic and diagnostic tools in these patients.