The exposure of PC cells to physiological concentrations of zinc (0.01–0.5 mM) can lead to cytotoxic cell death, which is characterized by up-regulation of the zinc transporter ZnT1 gene expression.312 Another study revealed that higher levels of zinc chloride (>50 μM) significantly reduced the proliferation of MIA-ZIP4 cells, suggesting that zinc activated the proliferation of PC cells only at comparatively low concentrations.393 Besides, zinc provided by MT may be working with transcription factors. The gene discussed is SLC39A4; the disease is pachyonychia congenita.