An increased risk of cancers was identified early in the HIV/AIDS epidemic. It was in the summer of 1981 that a series of young homosexual men in New York and California who developed a rare malignancy known as Kaposi Sarcoma (KS) was presented, coinciding with another series of patients who were diagnosed with an atypical pneumonia caused by the then called Pneumocystis carinii, now known as P. jirovecci. AIDS-Defining Cancers (ADCs) would comprise >95% of all the cancer cases detected in HIV positive patients with KS being by far the most common cancer seen in patients with HIV before the advent of Highly Active Antiretroviral Therapy (HAART). High-impact journals are those considered to be highly influential in their respective fields. The impact factor of journal provides quantitative assessment tool for grading, evaluating, sorting and comparing journals of similar kind. It reflects the average number of citations to recent articles published in science and social science journals in a particular year or period, and is frequently used as a proxy for the relative importance of a journal within its field. It is first devised by Eugene Garfield, the founder of the Institute for Scientific Information. The impact factor of a journal is evaluated by dividing the number of current year citations to the source items published in that journal during the previous two years.