Many cancers are caused by chemical irritation, the clearest case being lung cancer.
Also environmental and food chemicals, and those we already get in the uterus, cause cancer.
In Okinawa, Japan, breast cancer occurence among the population that follows the traditional lifestyle is only below 1%, but in Europe it is 13%. Also, the people of Okinava become ill after they move to the west and adopt western lifestyle. Therefore it is not about the genes. Doctors often belittle lifestyle factors in the prevention of cancer and especially in its treatment.
In addition to tobacco, obesity, alcohol, plastic molecules and chemicals, also the lack of vitamin D predisposes people to cancer. When the animal of African origin – us humans – is trying to live without the high amount of sun-generated vitamin D, the disease risks are increasing. A good vitamin D level in blood is 120–150 nmol / l. It’s worth having your blood tested for that, because it’s cheap. The risks of many other diseases are also reduced by raising vitamin D levels.