PTEN gene

Melanomas are a type of skin cancer. Although not quite as common as some, they can be very dangerous, due to their greater likelihood become malignant and spread than other cancers (thought to be because pigment cells are migratory cells already). They are also able to colonise most other areas of the body. All of which means they are extremely deadly.

Melanoma

Now scientists have discovered a set of genes, including the PTEN gene, which control how the melanoma cells shift rapidly between two shapes - one of the reasons why they can spread so easily. They can have rounded shapes, which they normally use to travel in the blood, or elongated shapes, which they use to travel through harder tissue, e.g. bone.
From studying fruit flies (whose cells have 5 different shapes as they grow during the flies' lifetime) it has been discovered experimentally, from switching off certain genes, which genes correspond to which shapes.
It has been found to be the same with melanoma cells - and specifically switching off the PTEN gene means that there are more elongated cells than rounded cells, and so can then more easily escape from the skin and advance to other areas. PTEN being deactivated is common in most cancers, for one in eight melanomas the gene isn't active.
Although this discovery at the moment is simply observational, hopefully it will lead to future options in helping treat and prevent melanomas.

Source: Genes help spread of shape-shifting skin cancer cells from the Conversation.