Expression of pyruvate dehydrogenase is an independent prognostic marker in gastric cancer

Figure 1 Immunohistochemical staining of pyruvate dehydrogenase in gastric samples. The typical diffuse cytoplasmic staining of the protein can be found in many gastric carcinoma and normal gastric tissues. A: PDH positivity was observed in the cytoplasm of NNM; B: PDH negativity was observed in NNM; C: PDH positivity was observed in the cytoplasm of well-differentiated gastric cells; D: Low expression of PDH was observed in gastric well-differentiated cancer cells. PDH: Pyruvate dehydrogenase; NNM: Non-neoplastic mucosa.

Figure 2 Relationship between pyruvate dehydrogenase expression level in cancer and non-neoplastic mucosa tissue from the same patient. The results showed that 123 patients had pyruvate dehydrogenase (PDH) co-expression (GC⁺/NNM⁺), 24 patients had GC⁺/NNM^- single expression, 76 patients had GC^-/NNM⁺ single expression, and 42 patients had double PDH negative expression; 147 cases (55.47%) showed positive PDH staining (Tumor ++ and Tumor +++) and 118 (44.53%) specimens displayed negative staining (Tumor - and Tumor +). PDH expression was much higher in the NNM tissue with positive staining in 199 (75.09%) specimens and negative staining in 66 (24.91%) specimens; P < 0.001. NNM: Non-neoplastic mucosa; GC: Gastric cancer.

Figure 3 Correlation between pyruvate dehydrogenase expression and prognosis of gastric cancer patients. Kaplan-Meier curves for cumulative survival of patients with gastric cancer (GC) according to GC tissue pyruvate dehydrogenase (PDH) expression shows that PDH expression in GC (A), in non-neoplastic mucosa (NNM) (B) and in both GC and NNM (C) was significantly associated with better overall survival. The Kaplan-Meier curves for cumulative survival rate stratified by Lauren grade, histological type and tumor-node-metastasis (TNM) stage also show that PDH expression was significantly associated with a better overall survival in each subtype of GC: intestinal-type GC (D), diffuse-type GC (E), differentiated type GC (F), undifferentiated type GC (G), and TNM stage I (H), II (I), III (J), and IV (K) subgroups.