Fragile histidine triad, also known as FHIT, may play a key role in differentiating humans from apes. Fragile histidine triad gene belongs to the histidine triad gene family. It has been shown that fragile histidine triad synergizes with VHL, another tumor suppressor, in protecting against chemically - induced lung cancer. Fragile histidine triad gene works as a tumor suppressor as it has been demonstrated in animal studies. The exact molecular function of FHIT is still partially unclear. It also acts as a tumor suppressor of HER2/neu driven breast cancer.