Molecular evidence for a viral etiology of human leukemias, lymphomas, and sarcomas

Angiosarcoma in Japan. A review of 99 cases

BACKGROUND

Angiosarcoma is rare, and information about its clinical features are limited. Therefore, a large scale study of angiosarcoma was performed in Japan.

METHODS

Through a nationwide Japanese study, 99 cases of angiosarcoma were collected and their clinicopathologic findings were summarized relative to predisposing risk factors.

RESULTS

The patient age at diagnosis was 3-92 years, (mean, 62 years), with a two to one male to female ratio. The head and face were the most common primary site (29 cases); other sites were liver (17); trunk (13): pleural cavity (6), chest wall (2), abdominal wall (2), buttock (2), inguinal region (1); heart (12); and extremities (7). The proven predisposing risk factors included chronic pyothorax for angiosarcoma in the pleural cavity (six), thorotrast in the liver (five), radiotherapy to the abdominal wall and buttock (four), and chronic limb edema of the forearm (one). Irrespective of primary sites, the majority of cases had metastases to lung in 72 cases, bone in 42, liver in 36, regional lymph nodes in 30, and adrenal gland in 24. The 2-year survival rate was 17%.

CONCLUSIONS

This study describes a different etiology in the development of angiosarcoma in patients from Japan compared with that of patients from Western countries, though the frequency of angiosarcoma among all soft-tissue sarcomas was similar in both areas. In Japan, chronic pyothorax, radiotherapy, and thorotrast proved to be distinctive causative factors of angiosarcoma.

Soft tissue sarcoma of the pleural cavity

Seventeen cases of soft tissue sarcoma (STS) developing in the pleural cavity were collected from Japanese hospitals, and their clinical and pathologic findings summarized. Eight of the 17 patients had a 15-year to 50-year (mean, 28.8) history of chronic pleural inflammatory disease (pleuritis, pyothorax, and pulmonary tuberculosis) before the onset of the pleural sarcoma. Histologically, malignant fibrous histiocytoma was the most common tumor type (11 cases), followed by angiosarcoma (four). The age at diagnosis of the sarcoma ranged from 15 to 74 years (mean, 58); the male-to-female ratio was 3.3:1. In the eight cases of sarcoma associated with chronic pleural inflammatory disease, male preponderance was more marked (7:1). The commonest presenting symptom was chest pain. A mass could be detected by chest roentgenograms in 13 patients and computed tomographic scans in 15 patients. No patient had distant metastases at first admission. Thirteen patients were treated by surgery, chemotherapy, and/or radiation therapy. Thirteen of the 17 patients died 1 to 87 months (mean, 14.2) after therapy for STS. The actuarial 1-year survival rate was 38.5%. These findings suggest that long-standing pleural inflammation might be an etiologic factor for development of pleural STS.

Theoretical mechanisms for synthesis of carcinogen-induced embryonic proteins: IV. The viruses

Speculations are developed for a mechanism by which oncogenic viruses can induce alterations in cells allowing them to express embryonic genes. It is suggested that if viral deoxyribonucleic acid, directly or via ribonucleic acid directed deoxyribonucleic acid polymerase activity becomes inserted at particular euchromatin - heterochromatin junctions of quasidifferentiated stem-like cells, then deheterochromatization may result, causing in turn derepression of genes for acidic protein phosphokinases. This sets into motion a series of events including altered acid protein repressors of embryonic genes which are repressed by uniquely weak type repressors. This explains how viruses can act as specific embryonic gene-inducing agents similar to chemical inducing agents such as the hepatocarcinogen ethinine.

Particles from mouse melanoma B16 containing reverse transcriptase and 70S RNA related to human melanoma cytoplasmic RNA

The mouse melanoma B16 contains particles encapsulating high molecular weight RNA of 60--70S size associated with a reverse transcriptase. The [3H]DNA synthesized by these particles possesses homology with RNA isolated from a hamster melanoma and from three human malignant melanomas.

DNA polymerase activity of cultured rheumatoid synovial cells

Cultured synovial cells from 8 patients with rheumatoid arthritis (RA) and 7 subjects without joint disease were assayed and comapred for RNA-directed and DNA-directed DNA polymerase activity. No activity was found in either RA or control specimens using a synthetic RNA template that specificically detects oncornavirus RNA-directed DNA polymerase. The DNA-directed DNA polymerase activity of RA specimens was increased (P less than 0.10) in the high-speed pellet fraction of cell lysates. The possible relationship of these finding to virus infection in RA is disscussed.

Sequences present in both human leukemic cell nuclear DNA and Rauscher leukemia virus

DNA synthesized by particulate fractions from human leukemic white blood cells has been subfractionated by hybridization to Rauscher leukemia virus 70S RNA followed by hydroxylapatite chromatography. The Rauscher-leukemia-virus-specific DNA fraction is shown to be complementary only to sequences present in the nuclear DNA of Balb/c mouse spleens infected by this virus and the nuclear DNA from human leukemic white blood cells, and not to sequences present in the nuclear DNA of normal Balb/c mouse spleens or the nuclear DNA of normal human white blood cells.

The presence of unique DNA sequences after viral induction of leukemia in mice. (RNA tumor virus-nucleic acid hybridization-insertion of viral DNA)

From previous studies, lymphocyte DNA from human leukemias and DNA from involved tissues of patients with Hodgkin's disease or Burkitt's lymphoma contain sequences that are absent from their normal counterparts. These sequences are related to those found in particulate elements associated with these neoplasias and possessing biochemical properties characteristic of RNA tumor viruses. Similar observations have been made of unique sequences related to those of the feline virus RD-114 and found in spontaneous mastocytomas in cats. Here we extend these results to the classical murine model of virus-induced leukemias. Splenic DNA from BALB/c mice with leukemia induced by Rauscher leukemia virus (RLV) possess some RLV-related sequences that do not exist in normal BALB/c DNA. Furthermore, these leukemia-specific sequences were absent in all other mouse strains examined, including AKR, a strain with a high incidence of spontaneous leukemia. The DNA of all noninfected mouse strains possesses considerable homology with the RLV genome. Temperature denaturation studies indicate, however, that although the RLV-related sequences found in all normal mice are similar to each other, they are not exactly homologous with RLV sequences. We conclude that RLV-induced leukemia in BALB/c results in the insertion of RLV sequences into cellular DNA that itself possesses only partial homology with the RLV genome.

Unique nuclear DNA sequences in the involved tissues of Hodgkin's and Burkitt's lymphomas

Previous studies have demonstrated that Hodgkin's, Burkitt's, and other human lymphomas contain particulate elements encapsulating 70S RNA and RNA-dependent DNA polymerase. [(3)H]DNA probes endogenously synthesized by these particles were used to demonstrate that the nuclear DNA of the lymphomas contain particle-related sequences that cannot be detected (less than 1/20th of a copy per genome) in the DNA of normal cells. This result agrees with our earlier findings in human leukemias. The data are inconsistent with any etiologic concept that invokes germ-line transmission of at least one complete copy of the particulate information associated with the malignancy. The unique sequences found in the nuclear DNA of Burkitt's and Hodgkin's tissues are related to each other but not to the DNA of the Epstein-Barr virus.