Lucknow, June 13 : Nearly 40 per cent of cancer cases are caused by tobacco, alcohol and pan masala, 4 per cent cases are genetic and 10 per cent are related to cleanliness, while there is no clue about 20 per cent cancer cases. Prof Pankaj Chaturvedi, Head Cancer Surgeon and Deputy Director of Tata Memorial Centre, Mumbai, said: "We have no clue as to what causes blood and bone cancer. It is very important to know the causes. There is a misconception about cancer in society." Prof Chaturvedi, in his presentation at the efficiency enhancement lecture on 'Victory over Cancer' held at the Lok Bhawan here on Monday, said that 70,000 cancer patients have been treated in Varanasi hospital so far and 25,000 patients are getting registered every year, yet there has been no drop in cancer patients getting admitted to cancer hospitals in Mumbai as they had thought of. Prof. Chaturvedi further pointed out: "The maximum number of patients of breast cancer and cervical cancer are found in women in urban areas. Cervical cancer patients are found more in rural areas than breast cancer patients. A unique gall bladder cancer occurs only to the people residing near and on the banks of the Ganges in Uttar Pradesh. Apart from India, this gallbladder cancer is more commonly found in Chile. "We are also doing research on this, but the cause of this cancer is yet to be known. Mouth cancer is the most common in men, followed by lung cancer. According to the geographical area, stomach and colorectal cancer gradually occurs. Cancer depends on lifestyle." /IANS