ACE2 and COVID-19: Additionally, although it has not yet been definitively proven that COVID-19 or post-COVID-19 syndrome (PCS) can cause thyroid carcinogenesis, due to the fact that thyroid cells have two key proteins, ACE2—the receptor for SARS-CoV-2, and TMPRSS2—a protease facilitating viral fusion with the cell, it is likely that having had COVID-19 or its long-term complications may contribute to the development of TC.