HSP90AB1 and thyroid cancer: Although the authors did not observe a change in the protein level of HSP90 in response to nelfinavir in RET-mutated thyroid cancer cells in vitro, the signaling of HSP90 client proteins—E-cadherin, tyrosine kinase Src (SRC) and connexin-34—was downregulated, suggesting nelfinavir-mediated post-translational modification of HSP90 [38].