[The plasma concentration of beta 2-microglobulin in the diagnosis of malignancy of the gastrointestinal tract (author's transl)].

In patients with various stages of carcinoma of the colon-rectum (n = 42) or stomach (n = 15) the plasma concentration of beta 2-microglobulin was determined. The upper limit for normal was evaluated in a control group of healthy people (n = 36) and was found to be 2.4 mg/l. 36% of the patients with carcinoma of the colon-rectum and 27% of those with carcinoma of the stomach had higher than normal beta 2-microglobulin values. In the group of colon carcinoma patients there was a positive correlation between the extent of the tumor and the beta 2-microglobulin concentration. Thus, an appreciable frequency of increased values (greater than 50%) was found only in advanced stage carcinoma. In patients with carcinoma of the stomach only occasionally increased values were observed, independent of the stage of the tumor. In conclusion, the plasma concentration of beta 2-microglobulin is no adjunct in the early diagnosis of carcinoma of the gastrointestinal tract.