For instance, if PPARγ expression is found to be upregulated in PAX8-PPARγ-negative tumours, it could reflect either a breakpoint between PAX8 and PPARγ in a location outside the primers used in the RT–PCR reaction, or a rearrangement between PPARγ and a non-PAX8 partner, or overexpression of wild-type PPARγ or point mutations in the PPARγ gene. Here, PAX8 is linked to neoplasm.