Foreign-body tumorigenesis induced by glass and smooth and rough plastic. Comparative study of preneoplastic events

Foreign-body (FB) tumorigenesis was induced in female CBH/H and CBA/H-T6 mice and their hybrids by sc implantation of about 0.2-mm thick, large (660-720 mm2) or small (210-400 mm2) pieces of glass, smooth-surfaced plastic, or roughened plastic (rigid unplasticized vinyl chloride vinyl acetate copolymer). The tumorigenic process was analyzed in the various implantation groups by the evaluation of tumor incidences and latencies, and by the determination of 1) frequency of originator ("parent") cells, 2) appearance of preneoplastic cells in FB-reactive capsule tissue, 3) expansion of preneoplastic cell clones throughout the tissue capsule, and 4) pace of cellular preneoplastic maturation in terms of time remaining until neoplastic autonomy. Established methods included transfer of preneoplastic FB-reactive tissue capsules to recipient animals (hybrids of CBA/H and CBA/Br or C57BL/10ScSn). Specific preneoplastic events or stages of FB tumorigenesis were affected differently, depending on the size, material, and surface properties of implants.

Foreign-body tumorigenesis by vinyl chloride vinyl acetate copolymer: no evidence for chemical cocarcinogenesis

We investigated whether vinyl chloride monomers, released from implants of vinyl chloride vinyl acetate copolymer (VCA), exerted cocarcinogenic activity and added thereby to the mechanism of foreign-body (FB) tumorigenesis. CBA/H and CBA/H-T6 mice were used. No evidence was found to indicate that chemical carcinogenic activity partakes in tumorigenesis by VCA implants. Hence it was concluded that VCA plastic is not suitable for the study of the combined process of FB/chemical cocarcinogenesis. Furthermore, experimental results obtained with VCA film implants were representative of FB tumorigenesis in the absence of demonstrable chemical carcinogenic activity.

Etiological factors, stages, and the role of the foreign body in foreign body tumorigenesis: a review

Attempts were made to analyze the process of foreign body (FB) tumorigenesis and to identify etiologically significant factors by correlating information in the literature and recent experimental data from our labroatory. It appears that the process of FB tumorigenesis is dependent on sequence of specific conditions as expressed by the following criteria: (a) cellular proliferation and tissue infiltration during acute FB reaction; (b) fibrosis of the tissue capsule surrounding the FB; (c) quiescence of the tissue reaction, i. e., dormancy and phagocytic inactivity of FB-attached macrophages; and (d) availability of a FB surface for direct contact with clonal preneoplastic cells. There is no indication that the initial acquisition of neoplastic potential and the determination of specific tumor characteristics are based on direct physical or chemical reaction between cells and the FB. These etiological key events occur presumably in mesenchymal stem cells associated with the microvasculature no later than during the acute stage of FB reaction and certainly long before clonal descendants of these cells are first found in contact with the FB surface. In fact, there is no reason to assume that cells with neoplastic determination may be present in normal tissue prior to the introduction of a FB and that the FB would only create the conditions required for stepwise preneoplastic maturation.

Antigenic Analysis of Human Cells and Tissues: Immunodiffusion Studies on Liver Tissue, White Blood Cells and Subcellular Fractions

Antisera were prepared in guinea pigs and other animal species against established human cell strains, human liver tissue and white blood cells. By means of agar-immunodiffusion numerous cellular antigens were discovered and defined. The cellular origin of the antigens was confirmed by excluding human plasma as the source. The distribution of these antigenic components in cell strains, liver tissue, white blood cells, subcellular fractions and on the erythrocyte membrane was studied. Liver tissue contained 19 of 20 antigenic components which had been described previously as a result of antigenic analyses on eight established human cell strains. Seven out of 17 antigenic components present in liver tissue were not demonstrable in three different specimens of human white blood cells. Therefore, the value of leukocytes as direct indicator of tissue antigenicity is questioned. Some of the antigenic components studied by immunodiffusion occur not only in soluble, diffusible form but were also detected on the human erythrocyte membrane as structural constituents. Specific associations between defined antigenic components and subcellular fractions have been established.

Carcinogenesis from polymer implants: new aspects from chromosomal and transplantation studies during premalignancy

Inbred CBA/H and CBA/H-T6 mice received implants of 15 X 22 mm plastic films. Plastic inserts and tissue capsules were cut in thirds at half monthly and monthly intervals. The first portion of the inserts and capsules was left in the original animal. The second portion was separated and individually transplanted into recipients that differed from the original animals with respect to the T6 marker chromosome. The third portion and all tumors which developed in original and recipient animals were examined by karyological, histological, and cultural methods. Film pieces caused tumors in recipient animals up to 9 months after transfer, capsule tissue only up to about 1 month after transfer. Tumors in original and corresponding recipient animals were identical in their chromosomal stemlines and pace of premalignant maturation. The karyotype of the stemline was never discovered among the film-attached cell population because there seemed to be no cell division. This points to the existence of a single, specific premalignant cell clone residing on the film surface in a dormant state of nondivision many months before tumor appearance. At the end, the (pre)malignant cells detached from the film, invaded the capsule tissue, and propagated to produce the tumor within about 4 weeks. The existence of a specific inhibition phenomenon during the premalignant phase is suggested.