To sum up our results, we managed to isolate a reproducible SP cell fraction of human gastric carcinoma cell lines for the first time. Those cells differed from the rest of the population regarding morphology and biological behaviour. They had the ability to build a population resembling the basic tumor population and therefore performed differenziation and asymmetric cell division. SP cells expressed potential stem cell markers like musashi 1 and Cd133 and also showed a high expression of genes that encode for stem cell properties. The so identified phenotypic and genetic factors showed a variable expression in tumor samples of patient series and might be applicable as prognostic factors in the diagnosis of gastric carcinoma.