IRS1 and myeloid sarcoma: Prominent among the inflammatory peptides produced by the adipocytes and the adipose tissue infiltrating macrophages is TNF-α which has been shown to impair insulin signalling in insulin sensitive tissues.13,18 This results in insulin resistance (IR), one of the hallmarks of MS, which stands out as the main end point underlying the clustering of CVD risk factors in MS.19,20 TNF-α promotes IR via serine phosphorylation of insulin receptor substrate 1 (IRS-1), as against the usual tyrosine phosphorylation.