Ito T, Kawabe R, Kurasono Y, Hara M, Kitamura H, Fujita K, Kanisawa M: Expression of heat shock proteins in squamous cell carcinoma of the tongue: an immunohistochemical study. J Oral Pathol Med 1998; 27: 18–22. © Munksgaard, 1998. Twenty‐four specimens of squamous cell carcinoma of the tongue were immuno‐stained for heat shock proteins (HSPs) to reveal differences in stainability among normal epithelium, dysplasia and carcinoma and to clarify the prognostic significance of HSPs in comparison with survival period, clinical stage, lymph node metastasis, histological grade, and p53 immunostaining. Normal epithelium was positively stained in the suprabasal layer for HSP60 and HSP70, but was negative for HSP27 and HSP90. Dysplastic lesions were positive for HSP27, HSP70 and HSP90, but stained variously for HSP60. In squamous cell carcinoma, the cytoplasm of suprabasal tumor cells was often positive for HSP27 and HSP90 (18/24, 17/24, respectively). Although HSP immunohistochemistry has revealed changes in HSP expression during tumorigenesis of squamous epithelium of the tongue, there was no correlation between HSP staining and survival period, stage, lymph node metastasis, histological grade or p53 immunostaining.

To clarify the events leading to the disruption of cell growth control that occurs during the development of pulmonary adenocarcinoma (AC), we used immunohistochemistry to evaluate the expression of G1 cycle regulators, cyclin D1, Rb protein (pRb), and p16 MTS1 protein and the tumour proliferation marker, Ki 67, both in AC of the lung and in its precursor lesion, atypical adenomatous hyperplasia (AAH). The frequency of lesions with cyclin D1 overexpression was relatively high in AAH (47-89%), but was decreased in early AC (28%) and overt AC (35%). The loss of pRb expression was rare in both AAH (0-18%) and early AC (0%), and was infrequent even in overt AC (13%). The loss of p16 expression was also relatively infrequent in both the premalignant and the malignant lesions (11-25%). Our results suggest that overexpression of cyclin D1 is an early event and plays an important part in tumorigenesis in the case of lung AC. However, cyclin D1 overexpression is not required for the development and maintenance of a malignant phenotype. It is likely that some cyclin D1-independent pathways other than Rb and p16 abnormalities have an important role in the malignant transformation from AAH to early AC.

No abstract