The effect of migration on the risk of nasopharyngeal cancer among Chinese.

The Chinese in California have an incidence of nasopharyngeal cancer roughly of the order of magnitude of the very high rate in Southeast Asia. Filipino migrants to Cal ifornia have a nasopharyngeal cancer risk intermediate to the high risk for Chinese and the low risk for Caucasians. A study of nasopharyngeal cancer mortality over the pe riod 1958 to 1972 shows a gradient of lower risk of the disease in the second and third generation of Chinese in California. While a genetic explanation of the racial sus ceptibility cannot entirely be ruled out, it can be said that the Chinese are at a very high risk of the disease, partly because of unusual exposure to an environmental agent.