Bolism in health and disease, as arginine is a precursor for several molecules with basically important biological functions, such as urea, nitric oxide, polyamines, proline, creatine, glutamate, and agmatine. [2,4] Though ARG2 is reportedly involved in tumor immune escape mechanisms, [5] its roles in human cancer remain to be fully elucidated. Here we showed that the majority of PDCs did not express ARG2 and that the presence of ARG2expressing PDCs was not significantly correlated with patient outcome. Instead, the presence of ARG2-expressing CAFs was found to be an independent predictor of poorer OS (HR = 1.582, P = 0.007) and DFS (HR = 1.715, P = 0.001) in PDC patients. The presence of ARG2 CAFs in PDC tissue was closely correlated with higher tumor grade, the presence of histological necrosis, the presence of CAIX-expressing stromal cells, and the presence of SLC2A1-expressing stromal cells in PDC tissue. ARG2-expressing CAFs were localized within and around necrotic areas in PDCArginase II in Pancreatic CancerTable 3. Correlation of expression of ARG2 in stromal cells with clinicopathological characteristics.Expression of ARG2 Characteristics Age, years ,60 60 Sex Male Female Size (mm) ,30 30 Pathologic tumor status T1 T2 T3 T4 Pathologic node status N0 N1 42 172 24 101 18 71 0.863 2 2 210 0 2 0 123 0 0 2 87 0 0.120** 50 164 32 93 18 71 0.414 130 84 70 55 60 29 0.118 71 143 46 79 25 64 0.189 No. of patients absence presenceExpression of ARGPCharacteristics Lymphatic invasion* 0, 1 2, 3 Venous invasion* 0, 1 2, 3 Intrapancreatic neural invasion* 0, 1 2, 3 Histological necrosis Absence PresenceNo. of patientsabsencepresenceP633825 64 0.835330 59 0.946133 56 0.776116 73 ,0.Expression of CAIX in stromal cells Absence Presence 167 47 121 4 46 43 ,0.Expression of CAIX in cancer cells Absence Presence 111 103 68 57 43 46 0.M0 M1 Stage IA IB IIA IIB III IV Tumor histological grade* W/D M/D P/D Tumor margin status Negative Positive Nerve plexusl invasion* Absence Presence19311578 11 0.Expression of SLC2A1 (Glut-1) in stromal cells Absence Presence 97 117 89 36 8 81 ,0.1 1 40 151 01 0 23 91 00 1 17 60 0 11 0.501**Expression of SLC2A1 (Glut-1) in cancer cells Absence Presence Tumor-infiltrating CD68+ macrophages*** lower higher Tumor-infiltrating CD66b neutrophils***+855827 62 0.1057233 54 0.55 11041 6514 45 30 0.001**lower higher1057629 58 ,0.Tumor-infiltrating CD4+ T cells*** lower 105 106 51 73 54 33 0.1599465 24 0.higherTumor-infiltrating CD8+ T cells*** lower 105 106 214 54 70 125 51 36 89 0.794336 53 0.higher TotalW/D, well differentiated tubular adenocarcinoma and papillary carcinoma; M/D, moderately differentiated. tubular adenocarcinoma; P/D, 47931-85-1 biological activity poorly differentaited adenocarcinoma. *Classified according to the classification of pancreatic carcinoma of Japan Pancreas Society. **Comparisons of qualitative variables are performed using the x2 24786787 test and otherwise Fisher’s exact test. ***Total number of patients are 211 and otherwise 214. doi:10.1371/journal.pone.0055146.tArginase II in Pancreatic CancerArginase II in Pancreatic CancerFigure 3. ARG2 was expressed mostly in CAFs within and around necrotic areas in PDC tissue. (A) Triple immunofluorescence shows that most of the dot-like staining of ARG2 (red) is present in a-SMA-positive fibroblasts (green). Cancer cells are positive for cytokeratins (blue). Nuclei are stained by DAPI (white). (B) Histology and immunohistochemistry of PDC tissue in low- (upper-photo of each pair of photos).Bolism in health and disease, as arginine is a precursor for several molecules with basically important biological functions, such as urea, nitric oxide, polyamines, proline, creatine, glutamate, and agmatine. [2,4] Though ARG2 is reportedly involved in tumor immune escape mechanisms, [5] its roles in human cancer remain to be fully elucidated. Here we showed that the majority of PDCs did not express ARG2 and that the presence of ARG2expressing PDCs was not significantly correlated with patient outcome. Instead, the presence of ARG2-expressing CAFs was found to be an independent predictor of poorer OS (HR = 1.582, P = 0.007) and DFS (HR = 1.715, P = 0.001) in PDC patients. The presence of ARG2 CAFs in PDC tissue was closely correlated with higher tumor grade, the presence of histological necrosis, the presence of CAIX-expressing stromal cells, and the presence of SLC2A1-expressing stromal cells in PDC tissue. ARG2-expressing CAFs were localized within and around necrotic areas in PDCArginase II in Pancreatic CancerTable 3. Correlation of expression of ARG2 in stromal cells with clinicopathological characteristics.Expression of ARG2 Characteristics Age, years ,60 60 Sex Male Female Size (mm) ,30 30 Pathologic tumor status T1 T2 T3 T4 Pathologic node status N0 N1 42 172 24 101 18 71 0.863 2 2 210 0 2 0 123 0 0 2 87 0 0.120** 50 164 32 93 18 71 0.414 130 84 70 55 60 29 0.118 71 143 46 79 25 64 0.189 No. of patients absence presenceExpression of ARGPCharacteristics Lymphatic invasion* 0, 1 2, 3 Venous invasion* 0, 1 2, 3 Intrapancreatic neural invasion* 0, 1 2, 3 Histological necrosis Absence PresenceNo. of patientsabsencepresenceP633825 64 0.835330 59 0.946133 56 0.776116 73 ,0.Expression of CAIX in stromal cells Absence Presence 167 47 121 4 46 43 ,0.Expression of CAIX in cancer cells Absence Presence 111 103 68 57 43 46 0.M0 M1 Stage IA IB IIA IIB III IV Tumor histological grade* W/D M/D P/D Tumor margin status Negative Positive Nerve plexusl invasion* Absence Presence19311578 11 0.Expression of SLC2A1 (Glut-1) in stromal cells Absence Presence 97 117 89 36 8 81 ,0.1 1 40 151 01 0 23 91 00 1 17 60 0 11 0.501**Expression of SLC2A1 (Glut-1) in cancer cells Absence Presence Tumor-infiltrating CD68+ macrophages*** lower higher Tumor-infiltrating CD66b neutrophils***+855827 62 0.1057233 54 0.55 11041 6514 45 30 0.001**lower higher1057629 58 ,0.Tumor-infiltrating CD4+ T cells*** lower 105 106 51 73 54 33 0.1599465 24 0.higherTumor-infiltrating CD8+ T cells*** lower 105 106 214 54 70 125 51 36 89 0.794336 53 0.higher TotalW/D, well differentiated tubular adenocarcinoma and papillary carcinoma; M/D, moderately differentiated. tubular adenocarcinoma; P/D, poorly differentaited adenocarcinoma. *Classified according to the classification of pancreatic carcinoma of Japan Pancreas Society. **Comparisons of qualitative variables are performed using the x2 24786787 test and otherwise Fisher’s exact test. ***Total number of patients are 211 and otherwise 214. doi:10.1371/journal.pone.0055146.tArginase II in Pancreatic CancerArginase II in Pancreatic CancerFigure 3. ARG2 was expressed mostly in CAFs within and around necrotic areas in PDC tissue. (A) Triple immunofluorescence shows that most of the dot-like staining of ARG2 (red) is present in a-SMA-positive fibroblasts (green). Cancer cells are positive for cytokeratins (blue). Nuclei are stained by DAPI (white). (B) Histology and immunohistochemistry of PDC tissue in low- (upper-photo of each pair of photos).
