CXCR4 and Carcinoma, Lewis Lung: For example, it was shown that knockdown of TNFR2 by shRNA rendered mouse Lewis Lung Carcinoma (LLC) more susceptible to TNF-induced apoptosis, accompanied by the down-regulation of Vegfa, Hgf, Plafg, and Cxcr4 expression, while the growth of such LLC cells in normal mice was normal33.