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The relationship between cartilage and invading neoplastic cells was studied in 32 cases of laryngeal cancer by histological and cytochemical methods. Cartilage invasion was present in 12 cases, 10 of which were in proximity or in contact with areas of calcification and ossification. It was significantly correlated only to tobacco consumption (P less than .05) and, in regard to glottic tumors, to tumor diameter greater than 3 cm (P less than .01). Histologically, neoplastic invasion in cartilage was massive in 2 cases, occurred in areas of ossification in 4, between cartilage and bone in 4, and in epiglottic cartilage in 2. In 3 of the cases with bone invasion, there was also new bone formation. Hyaline cartilage and bone resorption was due to tartrate-resistant acid phosphatase (TRAP)-positive giant cells; in epiglottic cartilage only mononuclear cells were present, some of which were TRAP-positive. These results show that neoplastic cells can promote not only resorption and formation of bone, but also resorption of cartilage, which is considered resistant to neoplastic invasion. The different types of resorbing cells in contact with hyaline cartilage and bone in laryngeal cancer, and elastic cartilage in epiglottic cancer, suggest that the structure of the tissue being resorbed can influence the type of resorbing cells.

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The in vivo localization of the glucocorticoid receptor (GR) was studied in cartilage and bone cells of femurs of young adult rats. Deparaffinized sections were treated with a polyclonal antibody raised against the amino-terminus of human GR; the immunoreaction was detected with the streptavidin-biotin amplification method. Histomorphometric, computer-assisted analysis of GR-positive cells was performed by counting the percentage of GR-immunostained cells in the proliferative and maturative/hypertrophic zone of the epiphyseal growth plate cartilage, and of the percentage of positive osteoblasts (OBs), osteoclasts (OCLS) and osteocytes (OCs) in the metaphyseal secondary ossification zone. Numbers of OBs and OCLs per mm of metaphyseal endosteal perimeter, and numbers of OCs per mm2 of trabecular area were also counted. Immunopositive cells were found both in cartilage and bone, with variable degree of nuclear and/or cytoplasmic immunostaining; immunonegative cells were present among the positive ones. Histomorphometry showed that about 54% of chondrocytes in the proliferative zone, and 55% of chondrocytes in the maturative/hypertrophic zone of the growth plate were labeled; in metaphyseal bone, 68% of OBs, 65% of OCs, and 98% of OCLs were GR-positive. The density of positive cells was 12.06 OBs/mm, 3.32 OCLs/mm, and 520.40 OCs/mm2. These results, for the first time obtained in vivo, show that GR is present in cartilage and bone cells, and that the degree of GR-immunostaining is variable in the same type of cell. This may be dependent on the cell cycle and stage of differentiation, and may reflect a variable cellular sensitivity to the stimulation of the glucocorticoid hormone.