This discovery of a bone tumor known as a fibrous dysplasia predates previous evidence of this kind of tumor by well over 100,000 years, David Frayer from the University of Kansas said.
Writing in the journal PLoS ONE, Frayer and colleagues from other institutions said while fibrous dysplasia in modern-day humans occurs more frequently than other bone tumors, "evidence for cancer is extremely rare in the human fossil record."
"This case shows that Neanderthals, living in an unpolluted environment, were susceptible to the same kind of cancer as living humans."
Because the cancerous rib, recovered in present-day Croatia, is an incomplete specimen the researchers said they were unable to comment on the overall health effects the tumor may have had on the individual.
Neanderthals had average life spans around half those of modern humans in developed countries and were exposed to different environmental factors, the researchers wrote.
"Given these factors, cases of neoplastic disease are rare in prehistoric human populations," they wrote. "Against this background, the identification of a more than 120,000-year-old Neanderthal rib with a bone tumor is surprising, and provides insights into the nature and history of the association of humans to neoplastic disease."