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Methods which dissociate intramolecular noncovalent bonds have been used to prepare soluble derivatives of cell-surface antigens. Applications of these techniques to human colon carcinoma are underway. Continuous tissue-culture strains derived from primary lesions were developed and shown to be composed of malignant epithelial elements. Parallel data on the preparation and activity of soluble materials in a murine model methylcholanthrene system reveal that although cultured cells are a satisfactory source for antigen extraction, they are poor targets of the immune response. The development of methods to quantitate the biologic activity of colon-specific, soluble materials may provide indicator systems to define the antigenic determinants, to permit purification, and to serve as assays of the efficacy of immunotherapy.

Leiomyosarcomas are malignant smooth muscle tumors characterized by a spectrum of histopathologic features and clinical behavior. Gene expression profiling of leiomyosarcomas may identify differential gene signatures that may allow for the clinical stratification of the tumors. Typically, surgical specimens from these tumors are large and manifest a variegated macroscopic appearance. Because of their large size at the time of diagnosis, sufficient tissue is available for regional and clonal heterogeneity assessment. However, if the gene expression profiles of samples taken from different locations in the tumors are drastically different, biologic classification on the basis of random sample analysis may not be adequate. Therefore, to assess intertumor and intratumor heterogeneity, the authors performed a gene expression study using leiomyosarcoma specimens from three excised sarcomas from an equal number of different patients. Comparisons between tumor and normal samples from the three patients as well as between carefully mapped peripheral and core specimens from the same tumor (excised from one of the patients), were performed. Analysis of the expression profiles demonstrated minimal intratumor variations compared with intertissue variations, indicating homogeneous tumor specific gene expression profiles. The authors also identified genes that are expressed differentially in tumor and normal tissue.

Spontaneously transformed hamster cells were examined for the presence of TSTA by employing the tumor rejection test. It was demonstrated that each of the spontaneously transformed cell lines as well as cells derived from tumors induced by these cells possess an individual distinct antigen, capable of evoking a significant anti-tumor immunity. The immunizing potential of these antigens and their specificity were not affected by either in vivo or in vitro environment. The results suggest that the spontaneously transformed hamster cells undergo antigenic modification, which resembles the TSTA of chemical-carcinogen induced tumors.

Experiments were designed to assess 1) relative immunity after adoptive transfer of spleen cells or serum from tumor-bearing mice to untreated syngeneic mice, and 2) the degree of tumor-specific transplantation immunity imparted by cells or serum relative to tumor size and the presence of metastases in the donor at the time of spleen cell or serum transfer or after in situ necrosis of the primary tumor by cryosurgery in a CDF1-sarcoma system. Viable lymphoid spleen cells or serum from normal mice had no effect on tumor growth. Serum from mice that had large tumors and gross metastases induced a protective effect similar to that found after cryosurgery of the primary tumor. Serum from mice with small tumors and spleen cells from animals bearing either small or large tumors failed to induce immunity consistently. In no instance did serum from tumor-bearing mice induce enhancement of tumor growth.

Tumor-specific DNA sequences or unique sequences have been found in a number of human cancer cells including gliomas but not in equivalent normal cells. In a continuing effort to further elucidate the nature of these sequences, thermal analysis using the hydroxyapatite technique was carried out on the various grades of astrocytomas. A recycled DNA molecular probe from Grade IV astrocytomas was annealed to the various grades of astrocytoma DNAs and to normal brain DNA which served as control. There was an increasing percentage of hybridization in direct proportion to the degree of malignancy. The same results were obtained using a recycled DNA probe from medulloblastomas. Thermal melt analysis of these same tumors revealed a Tm (melting temperature or temperature of reassociation) of about 83 degrees C, irrespective of degree or grade of malignancy. These results would indicate that the type of genetic DNA sequences or tumor-specific DNA sequences involved in this type of tumor is the same, whether the tumor is benign or malignant. The demonstration of the increasing percentage of hybridization based on the increasing degree or grade of malignancy and the further demonstration that the involved tumor-specific DNA sequences are the same irrespective of the degree of malignancy, justify the conclusion that the number of copies of these sequences determines the degree or grade of malignancy. Pending further laboratory confirmation, this fact may be assumed to be true with respect to cancers from other organ sites.

Thoracic duct lymph was drained for 28 days from a patient with disseminated malignant melanoma. Lymphocytes were separated from the lymph by centrifugation, and returned to the patient daily. Biochemical and hematologic parameters were monitored in blood and lymph, and were maintained at satisfactory levels throughout the period. Cell-mediated immunity and specific blocking activity directed against melanoma antigens were examined by the leukocyte adherence inhibition test. Blocking factors in drained lymph fell to undetectable levels after 6 days' thoracic duct drainage, whereas it took 9 days for serum blocking factors to fall to similar levels. Peripheral blood leukocytes demonstrated cell-mediated immunity against melanoma antigens before and throughout the period of drainage, except for the immediate postoperative period. Within 24 hours of closure of the thoracic duct fistula, serum blocking activity had returned, and 17 days later the patient died.

Carcinoembryonic antigen is only a tumor associated antigen and is less clinically useful than the original report suggested. However, the CEA assays in clinical use utilize reagents operationally defined by old criteria. There is now abundant evidence that “CEA” consists of a heterogenous family of related glycoproteins with shared, as well as distinctive, antigenic determinants. Antigenic differences can be demonstrated between some cancer sera “CEA” and various operationally defined tissue “CEA” preparations. Further definition of the biochemical and antigenic characteristics of serum and tumor tissue “CEA” is required in order to determine whether a more tumor specific antigenic determinant can be identified.

Utilizing the technique of hydroxyapatite chromatography, normal cellular DNAs were used to recycle off the repeat or normal sequences found in [3H]DNA copied off 70S RNA from malignant astrocytomas. The recycled [3H]DNA were then used to hybridize against DNAs from normal human brain tissues and DNAs from malignant astrocytomas or Grade IV astrocytomas. The results indicated the presence of tumor-specific DNA sequences in malignant astrocytomas, absent in normal brain tissues. The percentages were 88% and 7%, respectively. When recycled medulloblastoma 70S[3H]DNA probes were utilized against DNA'S FROM Grade IV astrocytomas and from normal brain, similar results were obtained. The respective percentages of hybridization were 67% and 7%. Thus it would appear that malignant gliomas contain tumor-specific DNA sequences which are not found in normal brain tissues.