Epidemiological peculiarities of cancers of the gall-bladder and larynx that distinguish them from other human neoplasias.
The purpose of this study was to elucidate the nature of the lack of an East-West difference in both gall-bladder cancer and laryngeal cancer as regards in their risk variations in space--a property that distinguishes them from other cancers. In practice, statistical analysis was used to obtain relevant information from the IARC data book, 1978-1982. Results of key importance are as follows: 1) the epidemiological trait of gall-bladder cancer was found to be a mirror image of that of laryngeal cancer in many respects including sex-discrimination of cancer risk and the geological distribution of both high-risk and low-risk populations. 2) Paradoxically, gall-bladder cancer and laryngeal cancer shared in common a small number of populations in both their high-risk groups as well as low-risk groups. It was indicated that the 2 cancers are under the control of 2 distinct risk modifiers in their risk variations in space: the one exerts a unidirectional impact on the risks of the 2 cancers in response to a change of the outer environment. The other exerts bidirectional impacts to produce increased risk of one neoplasia and decreased risk of the other. 3) Evidence was presented to suggest that the contribution of the inactivated tumor suppressor gene to carcinogenesis compared to that of the activated proto-oncogene was larger in the independent subfamily of gall-bladder cancer and laryngeal cancer than in any of the 2 subfamilies (Western type subfamily and non-Western type subfamily). The above marker of the independent subfamily was detectable in the female populations of the world, but not in the male populations. The significance of our findings is discussed from the point of view of hormonal carcinogenesis.
Kodama Research Institute of Preventive Medicine, Nagoya, Japan.
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D000367:Age Factors; D005260:Female; D005706:Gallbladder Neoplasms / Q000145:classification / Q000453:epidemiology* / Q000209:etiology; D014943:Global Health; D006801:Humans; D015994:Incidence; D007822:Laryngeal Neoplasms / Q000145:classification / Q000453:epidemiology* / Q000209:etiology; D008019:Life Style; D008297:Male; D015233:Models, Statistical; D009369:Neoplasms / Q000145:classification / Q000453:epidemiology* / Q000209:etiology; D000090063:Proto-Oncogene Mas; D012307:Risk Factors; D012737:Sex Factors