Development of squamous cell carcinomas (SCCs) involves alterations in the adhesive interactions in the epithelium and invasion through the basement membrane. Therefore, changes in the expression of receptors and ligands involved in cell‐cell and cell‐matrix adhesion may be essential for the transformation of a premalignant into a malignant lesion. The aim of this study was to examine if expression of specific cell adhesion molecules can be used as markers of malignant development. By immunohistochemistry, we examined the expression pattern of integrins α2β1, α3β1, α6β4 and laminin‐5 in biopsies from SCCs (n=18), premalignant lesions (leukoplakias, n=21) and non‐premalignant tissue with chronic inflammation (n=11). In poorly differentiated SCCs, patchy loss of α3β1, α6β4 and laminin‐5 expression was pronounced at the invasion front, whereas there was a tendency to increased expression of α2β1. Analogous to the SCCs, biopsies from the leukoplakias and the non‐premalignant inflammatory tissue showed alterations of the expression of α3β1 and α6β4 in the basal cell layers and of laminin‐5. However, a characteristic finding in biopsies from leukoplakias was loss of α2β1 and α3β1 in the suprabasal cells. There was no unequivocal expression of the adhesion molecules distinguishing between inflammatory tissue, premalignant, and malignant lesions.

With the object to disclose an association between laryngeal papillomatosis and laryngeal carcinoma, we reviewed 102 patients with laryngeal papillomatosis treated between 1950 and 1979. Seven cases of laryngeal carcinomas were recorded and 1 patient with spread of papilloma to the bronchial tree developed a bronchial carcinoma. The time between onset of papilloma and diagnosis of carcinoma was 4-55 years (mean 24 years). For laryngeal carcinoma the ratio of observed to expected cases was 88. Of the 8 patients developing respiratory tract carcinoma, 2 had received treatment with radiation and 2 had been treated with Bleomycin. Four of these 8 patients were known smokers. This study shows that papillomatosis is more often associated with laryngeal carcinoma than previously reported. It appears, however, that laryngeal papillomas alone seldom induce carcinomas. Apart from irradiation and smoking, Bleomycin could be an important co-factor.

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In order to study the connection between occupation and sinonasal cancer we have reviewed the files and histological sections of 70 patients (24 females and 46 males) treated at the Department of Oto-rhino-laryngology, National Hospital of Norway. Detailed information concerning previous occupations was obtained by telephone interviews according to a standardized questionnaire. This pilot study revealed a strong association between wood dust exposure and sinonasal cancer. Of 12 wood dust exposed men, 11 had been exposed exclusively to softwood. While squamous cell carcinoma was the predominant type of cancer in joiners, carpenters and loggers, non-Hodgkin lymphomas appeared to be associated with employment in saw- and planingmill firms. A nationwide case-control study is under preparation for further substantiation of the health hazards connected with exposure to softwood and other possible occupational factors related to sinonasal cancer.