Answer:
Studies have shown that cancer is not mainly caused due to hereditary or environmental factors but is caused due to random mistakes which occur in the DNA.
Studies have shown that even the tiniest of mistakes in the DNA can cause cells to multiply in an uncontrolled manner causing cancer. Mistakes in the DNA can cause tumour suppressing genes can cause cancer cells to grow and divide in an uncontrolled manner. About 66% of cancer are known to arise due to these random mistakes.