Shanghai local doctors have advised people to check themselves for naevus on the sole of foot.

They say these moles can develop into cancerous melanin pigment tumors, the fifth commonest cancer for males and the sixth commonest for females. Cancerous naevus of the sole is an aggressive tumor with poor treatment outcomes, and since they are located on the foot, many people don't notice them in time.

Doctors say repeated friction during walking is the main cause of pathological change in the growths.

(Shanghai Daily March 27, 2008)