Among the three genes, SPP1 is highly expressed in lung adenocarcinoma compared with normal lung tissue, but PECAM1 and PIK3R1 have low expression in lung adenocarcinoma compared with normal lung tissue, and the high expression of SPP1 is associated with poor prognosis (Figure 7(d)), while a positive prognosis is associated with high PECAM1 and PIK3R1 expression (Figures 7(b) and 7(c)). The gene discussed is PECAM1; the disease is lung adenocarcinoma.