Background. Gastric cancer is the second leading cause of malignant tu
mours in Mexico. The distribution of the histological types of this tu
mour has not been estimated from a population-based representative sam
ple. Methods. The histological types of gastric cancer according to th
e Lauren classification and selected socio-demographic characteristics
for 220 patients from different socioeconomic levels are reported. Th
e study population represents 66% of all new gastric cancer cases duri
ng 1989-1990 reported to the Mexico City Cancer Registry, The patients
attended four public hospitals, seven social security hospitals and f
our private hospitals in Mexico City, A second histological diagnosis
was performed by one pathologist. Results. No specific histological ty
pe of gastric cancer predominated since the estimated distribution for
intestinal gastric cancer was 44.5%, for diffuse gastric cancer 43.2%
(and the remaining 12.3% corresponded to indeterminate tumours). The
distribution of intestinal and diffuse gastric cancer did not vary sig
nificantly according to socioeconomic level or medical care unit and i
t showed a clear relationship with gender, the intestinal type of gast
ric cancer being more common among males. Conclusions. Mexico may not
have been affected by the gastric cancer epidemic at the beginning of
the twentieth century but the available information and the results of
this study are only useful to demonstrate that, currently, no histolo
gical type of gastric cancer (according to Lauren's classification) pr
edominates significantly in this country.