Model examination of chemoprevention with retinoids in squamous cell carcinomas of the head and neck region and suitable biomarkers for chemoprevention.

The prognosis for patients with head and neck tumors (HNSCC) is poor, due among other things to the high-risk factor for locoregional recurrence and/or second primary tumors. Extensive studies on chemoprevention of oral pre-cancers to stop carcinogenesis and to prevent recurrence and/or second primary tumors have failed to reach the desired effects. The toxicity of retinoids (RA) for example limits their dosage.

Immunohistochemical analysis of integrins αvβ3, αvβ5 and α5β1, and their ligands, fibrinogen, fibronectin, osteopontin and vitronectin, in frozen sections of human oral head and neck squamous cell carcinomas.

Integrins mediate the interaction of cells with the extracellular matrix and are believed to be involved in tumor cell survival and metastasis, and in tumor angiogenesis. We used immunohistochemistry of fresh-frozen human tumor tissues to analyze the presence of integrins αvβ3, αvβ5 and α5β1, which are believed to be involved in tumor growth and migration, together with integrin ligands, vitronectin, osteopontin, fibronectin and fibrinogen, in human oral squamous cell carcinomas. Samples of squamous cell carcinomas and control tissues from patients without cancer undergoing oral or maxillofacial surgery were frozen in liquid nitrogen within 30 min of removal.

Localization of telomerase hTERT protein in frozen sections of basal cell carcinomas (BCC) and tumor margin tissues.

In previous studies we demonstrated telomerase activity in frozen tissues from BCC and their tumor-free margins by the PCR ELISA. In this study we examined in the same frozen sections immunohistochemical presence of hTERT in the nucleus. After fixation in acetone and methanol followed by steaming we used for visualization the antigen-antibody reactions by APAAP.

Immunohistochemical determination of the appropriate anti-hTERT antibodies for in situ detection of telomerase activity in frozen sections of head and neck squamous cell carcinomas and tumor margin tissues.

In previous studies we demonstrated telomerase activity in frozen tissue from head and neck squamous cell carcinoma (HNSCC) and their tumor-free tumor margins. In the present study frozen sections from the same tissues were examined for in situ presence of hTERT. In preliminary investigations we established that the most suitable method of tissue preparation was fixation in acetone and methanol followed by steaming and visualization by APAAP.

Clinical significance of telomerase activity in basal cell carcinomas and in tumour-free surgical margins.

To distinguish the infiltrative from the non-infiltrative basal cell carcinoma (BCC), cell cycle markers are being used to supplement histopathological assessment, and proliferation markers are proving particularly useful. A successful radical therapeutic intervention depends on a clear histopathological diagnosis, especially for the tumour margins. For this purpose we investigated whether proof of telomerase activation is a suitable adjunctive molecular marker.