Abstract
Research during the past decade has indicated that most, if not all, human tumors possess tumor-associated antigens (1). This is based on in vivo and in vitro immunologic test systems which use intact tumor cells (2, 3), tumor cell homogenates (4) and subcellular fractions obtained by sonic disruption, enzyme digestion, and ultracentrifugation (5-7) as the source of antigen. There is also one report of a soluble tumor-associated antigen found in the fluid of a cystic melanoma (8).
Ideally, the use of soluble tumor antigens will not only eliminate a number of technical difficulties entailed in preserving and storing tumor cells, but will also enable the investigator to study patients sequentially in relation to their response to treatment. This soluble antigen, if shown to be tumor specific and immunogenic, may also be useful for specific immunotherapy. Recent success in salt extraction of soluble HL-A antigens (9) has led investigators to apply similar methods to the extraction of tumor-associated antigen from chemically induced hepatoma in guinea pigs (10). The antigenic activity of the extracted material was determined by the skin reactions in immunized and nonimmunized animals. This report presents preliminary evidence that human tumor-associated antigen can be separated by salt extraction and can be used in a multifaceted immunological evaluation of the cancer patient.
Materials and Methods. The patient, a 60 year old white male, had undergone resection of primary adenocarcinoma of the colon in 1962. Local recurrences were resected in 1964, 1966, 1968, and 1970. Radiation therapy or chemotherapy were not given. In November, 1971, he presented with a left abdominal mass. At laparotomy, a mucinous tumor was found to involve the spleen with multiple omental deposits. Splenectomy was done and the histological diagnosis was mucinous adenocarcinoma, metastatic to the spleen.
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