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Analysis of human cancer DNA for DNA sequences of human adenovirus type 4
Abstract:
We investigated whether human adenovirus type 4 (Ad4) might cause cancer in humans. Cell culture and animal model studies indicated that Ad4-induced human tumors should contain Ad4 DNA sequences. Thus Ad4 DNA was labeled in vitro (sp act, approximately 10(7) 3H counts/min/microgram) and hybridized in liquid phase with DNA extracted from human tumors. No viral sequences were detected in 31 squamous cell carcinomas of the lung, 5 adenocarcinomas of the lung, 4 oat cell carcinomas of the lung, 4 carcinomas of the stomach, 10 carcinomas of the colon, 3 carcinomas of the kidney, 3 carcinomas of the breast, 2 carcinomas of the ovary, and 6 Hodgkin's lymphomas. Reconstruction experiments with added Ad4 DNA indicated that the probe detected about 1 copy of 5% of the Ad4 genome per tumor cell. Therefore, these data were strong evidence (but did not prove) that none of these particular tumors were induced by Ad4.
Insights
Human adenovirus type 4 (Ad4) was investigated for its potential to cause human cancers. Studies found no Ad4 DNA in various human tumors, suggesting Ad4 does not induce these specific cancers.
Area of Science:
- Oncology
- Virology
- Molecular Biology
Background:
- Human adenovirus type 4 (Ad4) is a virus with unknown oncogenic potential in humans.
- Previous studies suggest viral DNA presence in virus-induced tumors.
Purpose of the Study:
- To determine if human adenovirus type 4 (Ad4) is associated with the development of specific human cancers.
- To investigate the presence of Ad4 DNA sequences in a variety of human tumor types.
Main Methods:
- Labeled Ad4 DNA was synthesized in vitro.
- Hybridization assays were performed using labeled Ad4 DNA and DNA extracted from human tumor samples.
- Sensitivity of the assay was confirmed through reconstruction experiments.
Main Results:
- No Ad4 DNA sequences were detected in 31 lung squamous cell carcinomas, 5 lung adenocarcinomas, 4 lung oat cell carcinomas, 4 stomach carcinomas, 10 colon carcinomas, 3 kidney carcinomas, 3 breast carcinomas, 2 ovarian carcinomas, and 6 Hodgkin's lymphomas.
- The assay was sensitive enough to detect approximately 1 copy of 5% of the Ad4 genome per tumor cell.
Conclusions:
- The absence of Ad4 DNA in the tested human tumors provides strong evidence against Ad4 being the causative agent for these specific malignancies.
- Further research may be warranted to definitively exclude Ad4's role in other human cancers or under different conditions.