Viruses and Cancer
F Peyton Rous...chicken sarcoma
first demonstrated in 1908 by Wilhelm Ellermand and Olaf Bang...causative agent of chicken leukemia
Sarah Stewart..discovered and isolated human cancer-causing virus
adenocarcinomas in mice were discovered in 1936...virus-induced
Unrecognized because:
most of the particles infect cells but do not induce cancer
cancer may not develop until long after infection
cancers are not contagious like viral diseases usually are
Transformation of Normal Cells into Tumor Cells
affect parts of the genome called oncogenes
Bishop and Varmus: Nobel 1989..cancer-inducing genes carried by viruses are actually derived from animal cells
oncogenic viruses: 10% of cancers
tumor cells undergo transformation
tumor specific transplantation antigen...antigen on cell surface
T antigen...antigen in nucleus of tumor cell
less round than normal cells and show abnormalities
DNA Oncogenic Viruses
human papillomavirus
Epstein-Barr virus
hepatitis B
RNA Oncogenic Viruses
only from family Retroviridae
human T-cell leukemia
Subtopic