Integrins and basement membrane proteins in skin carcinomas.

The topography of some integrins and basement membrane proteins in cutaneous basal cell carcinomas (BCC) and squamous cell carcinomas (SCC) has been studied by immunohistochemistry. The typical cell-to-cell distribution of alpha 2 beta 1 and alpha 3 beta 1 of normal epidermis becomes pericellular in both BCC and SCC cells. BCC and SCC also showed different patterns of expression of alpha 6 beta 4, the integrin normally located at the basal surface of basal epidermal keratinocytes. SCC showed high expression and pericellular distribution of alpha 6 beta 4, while BCC did not express alpha 6 beta 4 at all also in Western blotting. The basement membrane was markedly different in the two tumor types. Laminin and collagen type IV were conserved in the basement membrane zone of both tumors while nicein/kalinin was absent from BCC cells. The simultaneous loss of expression of alpha 6 beta 4 and nicein/kalinin in BCC cells but not in SCC cells indicates that alpha 6 beta 4 and one potential ligand may be co-regulated in both BCC and SCC. We suggest a role for this phenomenon in the pathogenesis of these epidermal tumors.

Expression and topography of integrins and basement membrane proteins in epidermal carcinomas: basal but not squamous cell carcinomas display loss of alpha 6 beta 4 and BM-600/nicein.

The expression and topography of some integrins and basement membrane proteins in cutaneous basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs) have been studied by immunohistochemistry and Western blotting. It has been shown that the typical cell-to-cell distribution of alpha 2 beta 1 and alpha 3 beta 1 found in normal epidermis is replaced by pericellular distribution in both BCC and SCC cells. BCC and SCC also showed different patterns of expression of alpha 6 beta 4, an integrin heterodimer normally lining the basal surface of basal epidermal keratinocytes: whereas SCC showed high expression and pericellular distribution of alpha 6 beta 4, BCC cells did not express this integrin at all. The absence of alpha 6 and beta 4 subunits from BCC extracts was confirmed by Western blotting. The molecular composition of the basement membrane was markedly different in the two types of epidermal tumors. Whereas laminin and collagen type IV were conserved in the basement membrane zone of both tumors, the molecular complex BM-600/nicein, which is recognized by the monoclonal antibody GB3 and is possibly identical to the previously described basement membrane glycoproteins kalinin and epiligrin, was absent from BCC cells. Then, the simultaneous loss of expression of alpha 6 beta 4 and BM-600/nicein in BCC cells but not in SCC cells indicates that alpha 6 beta 4 integrin and one of its potential ligands may be co-regulated in both BCC and SCC, thus suggesting a role for this phenomenon in the pathogenesis and clinical behavior of these epidermal tumors.

[Cryotherapeutic destruction of invasive tracheo-bronchial tumors. Personal case histories]. / Disostruzione crio-terapica dei tumori invasivi tracheo-bronchiali. Casistica personale.

Data are presented on 15 cases of invasive tracheobronchial tumours subjected to cryotherapy in 1984-85. The technique is indicated in patients who cannot be given surgical or radiation treatment and in cases of asphyxial syndrome requiring faster deobstruction than is obtainable with radiation treatment.

[Functional compromise of the small airways in subjects exposed to SiO2]. / Compromissione delle piccole vie aeree nei soggetti esposti a SiO2.

Aims of our study were: to evaluate small airway function of subjects with past or present silica dust exposure and normal spirometric values; to investigate whether small airway disease is related to radiographic signs of silicosis, to cumulative dust exposure (ES) and to cigarette smoking. Maximal expiratory flow at 50% (MEF50) and 25% (MEF25) of forced expired vital capacity were measured in 112 subjects, 69 with radiographic signs of silicosis, group I, and the remaining 43 with normal chest X-rays. Even if age and ES were significantly higher in group I, no significant difference in respiratory function tests and in prevalence of small airway disease was found between the two groups. In both groups small airway function was significantly negatively related to smoking habits, while it was independent of the other variables considered. Multiple regression analysis with MEF50 and MEF25 as dependent variables did not show any significant relationship. We conclude that small airway disease due to encroachment of bronchiolar walls by SiO2 deposition is masqued by the damage produced by cigarette smoking, even in the presence of radiographic signs of silicosis.