Many risk factors such as smoking and change of life style have been shown to promote genetic and adaptive epigenetic changes responsible for tumorigenesis. This study brings environmental temperature as a cancer causing factor to light. The cancer mortality rate (CMR) of a country was correlated with 17 different variables. Multivariate analysis of a total of 188 countries found that the average annual temperature (AAT) of a country might have a significant contribution to cancer death when compared with other factors such as alcohol and meat consumption. Univariate analysis found a negative correlation between AAT and CMR. All these countries were categorized into three temperature zones (zone I, -2 to 11.5 °C; number of countries, 38; zone II, 11.6 to 18.6 °C; number of countries, 32; and zone III, 18.7 to 30 °C; number of countries, 118). Out of the top-most 50 countries having the highest CMR, 26 (68.42 %), 10 (31.25 %), and 14 (11.66 %) belong to zone I, zone II, and zone III, respectively. Out of the least 50 countries having the lowest CMR, 1 (2.63 %), 4 (12.5 %), and 45 (37.5 %) belong to zone I, zone II, and zone III, respectively. CMR is low in those countries situated near to the Torrid zone (33(°) N to 23.5(°)S), but it is high for those countries situated away from these two latitudes. These data indicate that cold temperature may have a contribution in increasing tumorigenesis. High metabolic stress, which is the result of maintaining our body temperature against a cold environment, could be the possible cause for the higher cancer mortality.

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In this paper, we introduce a new generalization of geometric distribution which can also viewed as discrete analogue of weighted exponential distribution introduced by Gupta and Kundu(2009). We derive some distributional properties like moments, generating functions, hazard function and infinite divisibility followed by three methods of estimation of the parameters. A new characterisation of Geometric distribution have also been presented using the proposed distribution. Finally, we examine the model with real data sets.

A number of methods for categorization of carcinogens, including classification and ranking, have been examined and applied to 13 carcinogenic chemicals. Compounds known to be carcinogenic to humans ranked highly in the ranking systems. The TD50 approach was a satisfactory ranking system. The examination of the classification system of the International Agency for Research on Cancer, and the studies of the ranking systems revealed the importance of considering the underlying mechanisms of carcinogenesis. Some of the important problems of categorizing carcinogens are discussed.

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