Laminin immunodetection in tumorous and nontumorous disorders of human thyroid

Laminin distribution in tissues from surgically removed thyroids consisting in normal gland (5), Basedow's disease (5), thyroiditis (5), follicular adenomas (8), papillary carcinomas (8), follicular carcinomas (6) was studied using rabbit laminin antibody raised against murine laminin. Immunoperoxidase technique (Avidin-Biotin-Peroxidase Complex) was performed on (1) paraffin sections of fixed tissue (2) frozen sections for light microscopy examination. Vibratome thick sections (100 micron) and pre-embedding technique were used for electron microscopy study. Positive staining, was obtained only on frozen and vibratome sections and was found within basement membranes but never in epithelial cell cytoplasm. Laminin had a similar distribution in follicular adenomas, Basedow's disease and normal tissue. Nests of damaged cells in Hashimoto's thyroiditis lacked positive laminin immunostaining. In papillary carcinomas positive staining was found beneath the epithelial cells along the cores. In well differentiated follicular carcinomas the perifollicular laminin staining was preserved, whereas in poorly differentiated follicular carcinomas laminin staining was barely visible or absent.