Cell Marker Studies of Human Tumorigenesis

Spontaneous fusion in vivo between normal host and tumor cells: possible contribution to tumor progression and metastasis studied with a lectin-resistant mutant tumor.

“…An obvious question these and other studies (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31) raise is the relevance of spontaneous tumor-host cell fusion to clinical tumor progression. As noted already, a common feature of clinical tumor progression is the tendency for tumor cells to acquire more chromosomes as they become more anaplastic (19,47,48).…”

“…But it seems reasonable to suppose that tumor-host cell or tumor-tumor cell fusion followed by chromosome segregation could provide additional ways in which this might occur. There is, however, one seemingly compelling argument, put forward by Warner (66), against tumor-host cell hybridization being a frequent and relevant event in clinical tumor progression: the single enzyme phenotype of almost all tumors examined from females heterozygous for glucose-6 phosphate dehydrogenase (G-6-PD) (20).…”

“…Therefore, a tumor with a clonal origin would have a type A or B G-6-PD phenotype, whereas a tumor with a multicellular origin could have both types of enzyme. By exploiting this type of cellular mosaicism, most studies have shown that virtually all tumor samples thus far analyzed have a single-enzyme phenotype (20). However, one would anticipate that hybridization between tumor cells and host cells, if it occurred, should lead to tumors having a double (A + B) G-6-PD enzyme phenotype (66).…”

“…Close examination of the literature in this area, however, reveals that the vast majority of tumors examined in such G-6-PD phenotyping studied have been leukemias (20). Relatively few samples of carcinomas, and especially their metastases, have been tested.…”

A Role for Clonal Antigens in Cancer Diagnosis and Therapy<xref ref-type="fn" rid="fn5">5</xref>

“…The first premise is that the majority of spontaneously occurring human tumors arise by the clonal proliferation of a single cell. The mounting body of evidence, taken from the study of both human and animal tumors, that supports this concept has recently been reviewed (2,7). The importance of tumor clonality in the present context is that all the cells of the tumor will be antigenically similar to each other.…”