In line with the idea of a linear progression from less to more advanced forms, we found increased expression of α-SMA, COL1A1, and LOX in the more aggressive tumor component (ATC versus PTC or PTC tall cell versus a classical variant) in two TC patients of our series for whom a tumor with a mixed component or multiple tumor specimens were available (Figure S7B). The gene discussed is ACTA1; the disease is neoplasm.