Localization of the 92 kd gelatinase mRNA in squamous cell and adenocarcinomas of the lung using in situ hybridization

Abstract

We have used in situ hybridization for RNA to localize cells containing mRNA for the 92 kd gelatinase in carcinomas of the lung. We used archival material to analyze sections from 12 cases of squamous cell carcinomas of the lung including six stage I and three stage II and from three cases of adenocarcinoma of the lung. Presence of mRNA in the tissue was verified by in situ hybridization for gamma actin. The 92 kd gelatinase mRNA was found in all 12 squamous cell carcinomas tumors and was highly expressed in the tumor cells themselves. In addition, it was found in host stromal cells surrounding the tumor, but not in normal lung fibroblasts. In contrast it was not found in the adenocarcinomas of the lung or in the stroma surrounding these tumors. The mRNA for the 92 kd gelatinase was present in normal pulmonary tissue, bronchial epithelium, basal cell hyperplasia of bronchial epithelium, alveolar macrophages, and focally in bronchial mucous glands. It was not present in normal alveoli, vascular cells, cartilage, or most lymphocytes. We corroborated the presence of the mRNA for the 92 kd gelatinase by ribonuclease protection assay. The levels of mRNA for the 92 kd gelatinase in two specimens of squamous cell carcinoma were 6- to 10-fold greater than in the nonneoplastic tissue and two adenocarcinoma specimens.