Preclinical and epidemiological data indicate that activation of stearoyl-coA-desaturase (SCD-1), a Δ9 fatty desaturase responsible for the conversion of SFA to Monounsaturated fatty acids (MUFA) is potentially a critical factor both in the development of obesity [58] and cancer including breast cancer [59]. This evidence concerns the gene SCD and obesity due to melanocortin 4 receptor deficiency.