Mitochondrial C-tract and tobacco exposure in oral precancer cases.

Sir,

We would like to discuss about the article titled “Association between mitochondrial C-tract alteration and tobacco exposure in oral precancer cases” by Pandey et al.,[1] published in your journal. Pandey et al. had reported, “tobacco in both forms, chewable and smoke, is oncogenic and causes early changes in mitochondrial genome and the chances increase with increasing duration of tobacco consumption.”[1] In fact, to evaluate the risk of cancer, there are several tools. Detection of mitochondrial C-tract alteration can be used as a tool. However, it should be mentioned that mitochondrial C-tract alteration only implies cytogenetic change and it does not relate to exposure. To trace the relationship, monitoring of the exposure level by a biomarker is needed. A good biomarker that can be used in the present case is cotinine. Finally, the risk can also be modified by other factors. Betel chewing[2] and HPV infection[3] are good examples of these factors. These factors have not been ruled out by Pandey et al.[1]