Molecular Signatures of Infectious Agents in Human Cancer

As of 2000, experimental and epidemiological evidence has firmly established an association between various cancer sites and at least eight viruses, a few parasites (Schistosomes and liver fluke), and one bacterium (Helicobacter pylori). Approximately 15% of cancers worldwide, and 23% of cancers in developing countries, are now attributed to infectious agents. Most of this burden is related to viral infections (i.e, 10% worldwide, 17% in developing countries). Infectious agents represent, therefore, priorities in cancer prevention research. Cancer-associated viruses likely act, at least in part, by predisposing the cell to genetic changes, resulting in the progressive steps that lead to cancer growth. It may be beneficial, therefore, to identify early mutational changes in the progression to cancer. While involving primarily a distinct set of technologies from that used in developing molecular signatures, the knowledge gained from generating a genetic profile of cancer and its precancerous lesions may help predict the molecular signature of these lesions. Improvements in the detection of viruses and biomarkers of chronic infection have led to the identification of strong associations with cancer, particularly for human papillomavirus (HPV), hepatitis B virus (HBV), and human immunodeficiencyvirus (HIV). For some cancer associated viruses (e.g., HIV and hepatitis