SNHG15 and respiratory system cancer: A subgroup analysis further suggested that high expression of SNHG15 meant advanced TNM stage in digestive system cancers (HR = 2.96, 95% CI, 2.08–4.43; P=0.004), respiratory system cancers (HR = 2.95, 95% CI, 1.13–7.73; P=0.03) and female reproductive system cancers (HR = 2.61, 95% CI, 1.38–4.95; P=0.003), yet a irrelevant association between the expression level of SNHG15 and TNM stage in other systems was also observed (HR = 1.50, 95% CI, 0.09–26.42; P=0.78) (detail in Table 4).