shows both geographic and temporal variability. There are different patterns
of cancer at different places and different times. These patterns relate
both to habits and to environmental hazards.
The use of tobacco has resulted in lung cancer in North America and Europe
during the last half of the 20th century. Dietary habits underlie the high
incidence of stomach cancer in Japan, Northern China, Chile and Eastern
Europe. This tumor is associated with lower socioeconomic status. The
incidence falls in second generation Japanese who have moved to the United
States of America. Food preservation methods are associated with stomach and
liver cancers in West Africa and Southeast Asia. Techniques for pickling as
well as contamination with aflatoxins from mould are responsible.
Hepatitis B Virus is associated with liver cancer.