The second potential explanation for these results may lie in T-cadherin’s ability to downregulate the secretion of surfactant protein D (SP-D), as previously demonstrated in human lung A549 cells (a human bronchioloalveolar carcinoma cell line with properties of type-II alveolar cells) (Takeuchi et al., 2001). Here, SFTPD is linked to bronchioloalveolar carcinoma.