More importantly, PD1+CD4+ T cells were found to be associated with more numbers in tumour tissues than paratumour tissues, and the top 20 markers of these cells in tumour tissues (logfc > 0.95, p < .001) were associated with a lower probability of overall survival in ESCC (Figure 4F). The gene discussed is PDCD1; the disease is esophageal squamous cell carcinoma.