ACTA1 and neoplasm: Within the tumor stroma, few αSMA(+) SCSSNs and many αSMA(−) SCSSNs displayed donor XX signals (Fig. 3b–e, h), with donor chimerism seen in 4.6% (SD 2.4%) of αSMA(+) SCSSNs and 79% (SD 8.4%) of αSMA(−) SCSSNs.