KARACHI – One of the major reasons of deaths in underdeveloped countries, including Pakistan, is mouth cancer, which occurs as a result of genetic changes that take place due to the chewing habits of tobacco, paan, chhaliya, gutka, niswar and manpuri. These days gutka is considered to be the most hazardous and carcinogenic chewing agent in Pakistan. This was observed by Dr Saima Saleem, a doctorate research student of Prof Dr Abid Azhar, Director General of Khan Institute of Biotechnology and Genetic Engineering, University of Karachi. A Karachi University statement on Sunday pointed out that different types of unhygienic, unpacked and homemade guktas are also available in market like geelagutka (wet gutka) and sukhagutka (dry gutka). It said that for her study, Dr Saima collected a total of 260 OSCC patient’s tissue and blood specimens with informed consent from local hospitals of Karachi. The samples were later compared with blood samples of 260 age and sex matched controls. The histopathology of tissues of such patients helped in identifying the oral cancer. Patients’ blood and tissue samples extracted from the DNA aided in studying the genetic alteration as well. It was pointed out in the study that the early signs of oral cancer include appearance of white and red patches inside the mouth; this is considered as the early stage or premalignant stage of oral cancer. Along with this, a bruise, guilty, ulcer or discolorations inside or around lips, tongue or mouth are the most definite indications. At this stage cancer is usually curable through surgery. However, since initially these symptoms are absolutely painless as a result of which patient keeps ignoring them but the burning sensation and pain later on is unbearable. This is called the advance stage of oral cancer and the only possible treatment at this stage is chemotherapy and radiation therapy. The research study states that chewing habits of paan, chhaliya, tobacco, gutka, niswar and manpuri containing carcinogens (agents that cause cancer) causes mutation of tumour suppressor genes. Tumour suppressor gene is a gene that suppresses tumor. The germ line mutation/polymorphism of this gene has been reported to be involved in multiple steps of carcinogenesis. It has been reported in the research that they are hot spots of the mutation in the tumour suppressor gene. Mutagens can damage DNA and generate promutagenic lesions.