Gain- and loss-of-function studies of a target gene are generally expected to produce opposite phenotypes, however, this is not always observed [42, 43], particularly with regard to tumour suppressor genes [44], which may apply in the case of SPRY2. Ideally, the SPRY2 OE experiments would be repeated to further characterise the resultant phenotypes in HepG2 cells. This evidence concerns the gene SPRY2 and neoplasm.