EXPRESSION OF INSULIN-LIKE-GROWTH-FACTOR-2 MESSENGER-RNA IN HUMAN GASTRIC-CANCER

Insulin-like growth factor 2 (IGF2) stimulates cell proliferation and development in normal human growth. In several human cancers, the IGF2 gene is overexpressed and is thus considered to be a growth factor fo r tumors mediated through both the paracrine and autocrine pathways. H owever, the significance of IGF2 mRNA expression in gastric cancer has yet to be clarified. We semi-quantitatively measured the expression o f IGF2 mRNA in 57 Japanese cases of gastric cancer by means of the rev erse transcription polymerase chain reaction and also analyzed the rel ation between the IGF2 expression status and other clinicopathologic f actors. We also performed immunohistochemical staining for IGF2. In 41 of 57 cases (72%), the expression of IGF2 mRNA was greater in tumor t issue (T) than in normal tissue (N). The average tumor/normal (T/N) ex pression ratio of IGF2 mRNA corrected for that of control gene mRNA wa s 1.42, while ranging from 0.36 to 3.65. The T/N ratio of infiltrative -type cancers was greater than that of expanding-type cancers (p<0.05) . The cases with lymphatic permeation showed a greater T/N ratio than those without lymphatic permeation in expanding-type cancers (p<0.05). Immunohistochemical staining revealed IGF2 to be detected in cancer c ells themselves, especially at the margin of the cancer tissue. The IG F2 gene may thus play an important role in lymph vessel permeation esp ecially in expanding-type gastric cancers.