Expression of Po66-CBP, a galectin-8, in different types of primary and secondary broncho-pulmonary tumors

The monoclonal antibody Po66 is an IgG1 immunoglobulin isolated from a human bronchial squamous carcinoma and directed against a carbohydrate binding protein, Po66-CBP, belonging to the galectin family involved in neoplastic processes. This Po66 antibody has been shown to be useful for immunoscintigraphic detection of squamous cell carcinoma metastasis. We examined the expression of Po66-CBP in a wider range of primary or secondary malignant tumors of the lung of various histological types. We studied 52 specimens of broncho-pulmonary tumors including 41 primary squamous, glandular or neuro-endocrine tumors and 11 secondary tumors of glandular, connective tissue, melanocytic or germinal origin as well as 9 extra-pulmonary primary tumors with histological types similar to lung metastases. An immunohistochemical study was performed using an amplification system on paraffin-embedded sections. All histological types were positive for Po66 antibody, the cell origin giving no influence on the expression of Po66-CBP. There was however a relation between Po66-CBP expression and the degree of differentiation notably for squamous cell cancer and neuro-endocrine tumors. The metastatic character of the tumor tissue did not affect Po66-CBP expression.