Thank you for the question. The most important sign of a mole becoming cancerous is the evolution of the mole or changes to a mole. If the mole is growing quickly in size, and becoming more raised and painful, I would advise you to see your doctor or dermatologist get it checked out.
The common signs to look out for a suspicious mole include:
1. A - Asymmetry. The mole looks irregular and does not appear symmetrical
2. B - Bleeding.
3. C - Colour. If the colour of the mole is uneven eg. darker in some areas and lighter in other areas.
4. D - Diameter. The size of the mole is greater that 6mm
5. E- Evolution. The mole is becoming growing and enlarging.
If these signs are present, you should seek professional medical advice to rule out melanoma or mole cancer. It is important to catch a mole cancer early as the prognosis of melanoma when detected early is very good, while a late diagnosis has a much poorer prognosis.