Heterogeneity of PTEN and PPAR‑γ in cancer and their prognostic application to bladder cancer

: The aim of the present study was to determine the prognostic value of peroxisome proliferator-activated receptor-γ (PPAR-γ) and phosphatase and tensin homologue deleted on chromosome ten (PTEN) for bladder cancer. Data were collected from The Cancer Genome Atlas (TCGA), a public database, and were analyzed to assess PTEN and PPAR-γ heterogeneity as well as distinct trends in bladder cancers. Furthermore, PPAR-γ and PTEN expression levels and their association with one another were evaluated. Finally, the prognostic significance of PPAR-γ and PTEN for bladder cancer was validated in vivo using clinical samples. Based on the TCGA database, PTEN levels were significantly increased in bladder cancers (P<0.001); whereas PPAR-γ expression was downregulated in the same samples (P<0.05). Furthermore, linear correlation analysis indicated that in bladder cancers, PPAR-γ and PTEN are inversely correlated (P<0.001). The assessment and analysis of clinical samples revealed that PPAR-γ was significantly elevated in tumor tissues (P<0.001); however, PTEN was downregulated in cancer tissues (P<0.001). Furthermore, PPAR-γ expression determined by immunohistochemistry grey level (P=0.002) was also elevated in high-grade and invasive bladder cancers compared with low-grade and superficial tumors, whereas PTEN levels exhibited the opposite in this analysis (P=0.001). In individuals with lymphoid metastasis, PPAR-γ was significantly increased (P<0.001), and PTEN was significantly decreased (P<0.001). Pearson analysis revealed a significant negative correlation between PPAR-γ and PTEN expression (r=-0.604, P<0.05). In conclusion, tissue heterogeneity was observed with respect to PPAR-γ and PTEN expression in bladder cancer. PTEN and PPAR-γ expression are negatively correlated and may be excellent indicators of bladder cancer tumorigenesis and progression.