Weakening link to colorectal cancer?

Abstract

The catalytic γ-subunit of the enzyme phosphatidylinositol-3-OH kinase (PI(3)Kγ) relays signals from G- protein-coupled receptors at the cell membrane and mediates leukocyte responses to chemokines and chemoattractants^1,2,3. Sasaki et al.⁴ report that mice that cannot produce PI(3)Kγ have a high incidence of colorectal carcinomas, causing weight loss and premature death. However, PI(3)Kγ-null mouse strains have been independently generated in three other laboratories; none of these mice developed tumours and their weight and lifespan were normal. This casts coubt on the idea that loss of functional PI(3)Kγ leads directly to transformation of colon epithelial cells and tumour progression.