ERBB2 and gastric cancer: Furthermore, we analysed whether the expression of two molecules often involved in gastric cancer, p53 (involved in cell cycle control and apoptosis, and often overexpressed when mutations are present) and neu (or erbB2, a receptor tyrosine kinase that can be overexpressed due to the gene amplification, Falck and Gullick, 1989; Houldsworth et al, 1990) might be associated with prognosis in gastric cancer, even though they are presumably associated with early events in gastric carcinogenesis.