Our analysis determined the correlation between JCHAIN mRNA expression and immunophenotyping, including BRCA, LIHC, SARC, LUSC, OV, LUAD, KIRP, BLCA, PRAD, LGG, and UCEC, and differential phenotypes of JCHAIN expression could be found in different immunosubtypes within the same cancer, e.g., in BRCA, C1-C3, C6 expression was significantly higher, while C4 expression was lower (Figure 3A). The gene discussed is C4A; the disease is cancer.