Carbohydrate antigens in human lung carcinomas

Lung carcinomas represent a heterogeneous group of tumours with large variations in the biochemical, clinical, morphological and pathological manifestations. Despite the neuroendocrine features of small cell lung cancer (SCLC), it is today generally accepted that all types of lung cancer emanate from a common endodermally derived multipotent stem cell of the bronchial epithelium. NCAM (neutral cell adhesion molecule) has been shown to be a sensitive marker of SCLC. The presence of NCAM, with the alpha (2,8) polysialic acid units characteristic of embryonal NCAM, in SCLC and in a portion of NSCLC, seems to correlate with the malignant behaviour and prognosis of the tumours, suggesting that NCAM may have a functional role in the clinicopathological manifestations of lung cancer. Fuc-GM1 with 2-hydroxy fatty acids as a characteristic component of the ceramide has been found to be a unique ganglioside of SCLC, detected in the tissues as well as in serum from SCLC patients using specific monoclonal antibodies. Accumulation of sialylated and fucosylated polylactosamine type 2 carbohydrate glycolipid and glycoprotein antigens was found in serum and tissues of lung tumours in accordance with what is described in gastrointestinal carcinomas, and these antigens may be regarded as general carcinoma antigens irrespective of organ. Sialylated and fucosylated type 1 antigens, and gangliosides with NeuAc alpha (2,6)Gal linkage were also accumulated in lung cancer. The human immune system has been found to recognize lung cancer carbohydrate antigens, which might be human lung cancer autoantigens.