IRS1 and hepatocellular carcinoma: LAR transcript knockdown in McArdle RH7777 rat hepatoma cells [12-14] leads to a marked elevation in IR autophosphorylation, whilst a similar loss in HEK293 cells appears to have no effect on IR or IRS1 phosphorylation but instead, results in post-receptor insulin resistance as evidenced by impaired Akt and MAPK phosphorylation [22].