The Ph. D thesis was discussed at the College of Science at the University of Basrah (Molecular characterization of human polyomaviruses in cancer patients in Basrah City). It showed the researcher's thesis (Akeel Abd Ali Abdul Sahib) studying human polyomaviruses. The thesis aims to identify the presence of four types of human polyomaviruses from the Karolinska Institute, Washington University, Malawi, and St. Louis, and study their molecular characteristics using the polymerase chain reaction technique, where two types of them were diagnosed, namely the Washington University polyomaviruses and the Karolinska Institute polyomaviruses. The study concluded that there are two types of human polyomaviruses in many patients with colon, breast, thyroid, and rectal cancer. The study recommended conducting a broad survey of other types of these viruses and studying the relationship in causing the disease for these viruses.