Similar to the overall transcriptional profile of cancer cells in the GG component samples, surfactant-associated proteins (SFTPA1, SFTPA2, SFTPB, SFTPC, and SFTPD) were highly expressed, and the expression level was higher than that of other cancer cell subclusters of the GG component samples (Figure 3C). The gene discussed is SFTPA2; the disease is cancer.