SUNSCREENS AND CANCER

Sunscreens contain chemicals that confer protection from the UV radiations.
Mostly the sunscreen ingradients protect from UV-B light. UV-A protection is not offered by many sunscreens.
Some the ingredients of sunscreens are:

• PABA
• PBI (Phenylbenzimidazole)
  
• Octocrylene
• Octylmethoxycinnamate
• Benzophenone-3
• Micronized titanium oxide and zinc oxide particles.

Most of the ingradients used offer protection against UV-B and not UV-A, which is more deadly then UV-B.
UV-A causes malignant melanoma, which is responsible for 75% 0f the skin cancer related deaths, indicating the deadliness of the disease.

They are beneficail in that they provide protection against UV-B and thus prevent Squamous cell carcinoma and Basal cell carcinoma. (They are non-malignant skin cancers. The curable rate is also high for them.)

There are many disadvantages conceived with the use of sunscreens.

The titanium oxide and zinc oxide particles have cytotoxic and carcinogenic properties.
The ingredients like Bezophenone, octocrylene, octylmethoxycinnamate have been shown to absorb into the skin and produce reactive oxigen species(ROC). ROC's under illumination bring about alterations in the DNA that may lead to cancer.

Many sunscreen ingredients have been shown to produce singlet [o] which damages the DNA.

Apart from the above mentioned, other potential disadvanatges with the use of sunscreens are:

• Using sunscreens reduces melanin production. this makes us more susceptible to radiation damage.
• The absense of UV-a filters combined with a long exposure to sun incrases the chances of melanoma.
• Less Vitamin D poduction