Cancer is a group of over 100 diseases marked by uncontrolled cell growth that can form malignant tumors and spread, affecting roughly 90.5 million people globally in 2015—by 2019, annual new cases had grown to 23.6 million with 10 million deaths. Nearly a third of cancer deaths stem from modifiable lifestyle factors like smoking, alcohol, obesity, and poor diet, while 16–18% are caused by infections (such as Helicobacter pylori, hepatitis B/C, and HPV), and only 5–10% arise from inherited genetic defects; notably, HIV doesn't cause cancer directly but increases risk through immune deficiency. Prevention includes not smoking, maintaining a healthy weight, limiting alcohol and processed meat, and vaccination against hepatitis B and HPV—which nearly eliminates those virus-caused cancers—while screening is especially effective for cervical and colorectal cancers. Treatment typically combines surgery, radiation, chemotherapy, and targeted therapy, with emerging immunotherapies that harness the immune system, and palliative care for advanced disease; five-year survival rates average 80% for children under 15 in developed countries and 66% for all ages in the US. The most common cancers are lung, prostate, colorectal, and stomach in men; breast, colorectal, lung, and cervical in women; and acute lymphoblastic leukemia and brain tumors in children (except in Africa, where non-Hodgkin lymphoma dominates). The term "cancer" derives from the ancient Greek karkinos (crab), coined by Hippocrates and Galen, and the global economic cost was estimated at US$1.16 trillion per year as of 2010.