The increased longevity of humans over the past century can be significantly attributed to advances resulting from medical research. Among the major benefits of medical research have been vaccines for measles and polio, insulin treatment for diabetes, classes of antibiotics for treating a host of maladies, medication for high blood pressure, improved treatments for AIDS, statins and other treatments for atherosclerosis, new surgical techniques such as microsurgery, and increasingly successful treatments for cancer. New, beneficial tests and treatments are expected as a result of the Human Genome Project. Many challenges remain, however, including the appearance of antibiotic resistance and the obesity epidemic.