White spots on nails can be caused by various factors, including injury, fungal infections, allergies, certain medications, and systemic illnesses. However, it is important to note that white spots on nails are usually harmless and do not necessarily indicate a serious health condition.

Regarding cancer, melanoma can develop under and around the fingernails and toenails, but it is rare. White spots on nails are not a definitive sign of nail cancer, and other symptoms such as a bump or nodule under the nail, a band of color on the nail, or nail splitting should also be present.

As for product details, some chemicals used in the application and removal of acrylic or gel nails can damage nails and cause white spots. Additionally, a positive patch test to triethylene glycol, which is found in some nail products, can cause white striations, macules, and patches on the nail plate.

In summary, white spots on nails can have various causes, but they are usually harmless. They can be caused by injury, fungal infections, allergies, certain medications, systemic illnesses, or chemicals in nail products. White spots on nails are not a definitive sign of nail cancer, and other symptoms should also be present.