Ribonucleotide reductase M2 subunit is a novel diagnostic marker and a potential therapeutic target in bladder cancer

Morikawa T, Maeda D, Kume H, Homma Y & Fukayama M
(2010) Histopathology 57, 885–892 Ribonucleotide reductase M2 subunit is a novel diagnostic marker and a potential therapeutic target in bladder cancer Aims: To examine the immunohistochemical expression and function of ribonucleotide reductase M2 subunit (RRM2), a gemcitabine‐related molecule, in bladder cancer. Methods and results: One hundred and seventeen bladder specimens on a tissue microarray were immunostained for RRM2. Positive RRM2 staining was observed in none of 14 examples of non‐neoplastic urothelium, none of four low‐grade urothelial carcinoma (UC), 69 of 83 (83%) high‐grade UC, three of three (100%) squamous cell carcinoma and 12 of 13 (92%) lymph node metastasis of UC. RRM2 overexpression was associated significantly with muscularis propria invasion in UC patients who had undergone radical cystectomy (P = 0.005). Immunohistochemistry for RRM2 was then applied to small biopsy specimens of 15 cystitis with reactive atypia cases and 25 urothelial carcinoma in‐situ (CIS) cases. Positive RRM2 staining was found in one of 15 (6.7%) cystitis with reactive atypia cases and in 24 of 25 (96%) CIS cases. Finally, UM‐UC‐3 bladder cancer cells were transfected with RRM2 siRNAs and cell growth was evaluated. Knockdown of RRM2 protein markedly inhibited cell growth. Conclusions: We have shown frequent overexpression of RRM2 protein and its possible role in bladder cancer. Our results suggest that RRM2 is a novel diagnostic marker and a potential therapeutic target in bladder cancer.     

Clinicopathological correlation and prognostic significance of sonic hedgehog protein overexpression in human gastric cancer

Objectives: This study investigated the expression of Sonic Hedgehog (Shh) protein in gastric cancer, and correlated it with clinicopathological parameters. The prognostic significance of Shh protein was analyzed. Methods: Shh protein expression was evaluated in 113 cases of gastric cancer and 60 cases of normal gastric mucosa. The immunoreactivity was scored semi quantitatively as: 0 = absent; 1 = weak; 2 = moderate; and 3 = strong. All cases were further classified into two groups, namely non-overexpression group with score 0 or 1, and overexpression group with score 2 or 3. The overexpression of Shh protein was correlated with clinicopathological parameters. Survival analysis was then performed to determine the Shh protein prognostic significance in gastric cancer. Results: In immunohistochemistry study, nineteen (31.7%) normal gastric mucosa revealed Shh protein overexpression, while eighty-one (71.7%) gastric cancer revealed overexpression. The expression of Shh protein were significantly higher in gastric cancer tissues than in normal gastric mucosa (P < 0.001), which was statistically correlated with age (P = 0.006), tumor differentiation (P < 0.001), depth of invasion (P = 0.042), pathologic staging (P = 0.017), and nodal metastasis (P = 0.019). We found no significant difference in both overall and disease free survival rates between Shh overexpression and non-expression groups P = 0.168 and 0.071). However, Shh overexpression emerged as a significant independent prognostic factor in multivariate Cox regression analysis (hazard ratio 1.187, P = 0.041). Conclusions: Shh protein expression is upregulated and is statistically correlated with age, tumor differentiation, depth of invasion, pathologic staging, and nodal metastasis. The Shh protein overexpression is a significant independent prognostic factor in multivariate Cox regression analysis in gastric cancer.     

Nuclear staining of claudin‐18 is a new immunohistochemical marker for diagnosing intramucosal well‐differentiated gastric adenocarcinoma

Diagnosis of gastric adenocarcinoma using small biopsy samples is occasionally difficult. Various markers have been employed for improving the diagnostic accuracy, but there remains room for improvement. A total of 129 endoscopically biopsied samples were studied, consisting of 104 intramucosal tubular adenocarcinomas, 24 non‐cancerous lesions and one cancer sample originally suspected of non‐cancer but revised as cancer after immunostaining. We evaluated the association between histopathology and immunohistochemical expression of MUC1, HER2, p53, CEA, E‐cadherin, β‐catenin and claudin‐18. Regarding β‐catenin and claudin‐18, not only membranous expression (β‐catenin(M) and claudin‐18(M)) but also nuclear expression (β‐catenin(N) and claudin‐18(N)) were analyzed. When subtyped with mucin core protein expression, the gastric‐type cancers dominantly expressed claudin‐18(M), while claudin‐18(N) was significantly encountered in intestinal‐ and mixed‐types. Expression of MUC1 (P = 0.0010), HER2 (P = 0.0173), p53 (P = 0.0002), CEA (P = 0.0019) and claudin‐18(N) (P < 0.0001) revealed significant correlation with gastric cancers. Negative correlation of claudin‐18(M) (P = 0.0125) was also noted. MUC1 and p53 were negative in non‐cancer lesions. The non‐cancer group exceptionally expressed HER2 and β‐catenin(N). Membranous expression of E‐cadherin was consistent in both groups. Logistic regression analysis showed that MUC1 (P = 0.0086), p53 (P = 0.0031), claudin‐18(M) (P = 0.0158) and claudin‐18(N) (P = 0.0190) were independently associated with gastric cancers. Nuclear expression of claudin‐18 should be the novel diagnostic marker for gastric cancer.     

Early HER2 dysregulation in gastric and oesophageal carcinogenesis

Fassan M, Mastracci L, Grillo F, Zagonel V, Bruno S, Battaglia G, Pitto F, Nitti D, Celiento T, Zaninotto G, Fiocca R & Rugge M
(2012) Histopathology  61, 769–776 Early HER2 dysregulation in gastric and oesophageal carcinogenesis Aims: To explore human epidermal growth factor receptor 2 (HER2) status in the histological phenotypes [metaplasia, intraepithelial neoplasia (IEN, i.e. dysplasia), and adenocarcinoma] involved in the morphogenesis of both intestinal‐type gastric cancer (GC) and Barrett’s adenocarcinoma (BAc). Methods and results: A consecutive series of 275 samples of stomach and oesophagus tissue (representing the whole spectrum of the phenotypic changes involved in gastric and Barrett’s carcinogenesis) was studied. HER2 status was assessed by applying two immunohistochemistry (IHC) protocols, using the antibodies 4B5 and CB11. Dual‐colour silver chromogenic in‐situ hybridization (SISH) was also performed on the same tissue samples. In both oesophageal and gastric samples, the rate of HER2 overexpression rose significantly from low‐grade to high‐grade IEN to adenocarcinoma (P < 0.001), with the two IHC protocols showing consistent staining (consistency 95%; k = 0.78; P < 0.001). Intratumour heterogeneity was documented in both GC and BAc (using both IHC protocols). The rate of HER2 amplification (using SISH) increased significantly along with IEN dedifferentiation (P < 0.001). Neither native nor metaplastic mucosa samples (obtained from either stomach or oesophagus) ever showed HER2 amplification. There was excellent agreement between HER2 amplification and protein overexpression (both IHC protocols: SISH/4B5––consistency 97.8%, k = 0.89, P < 0.001; SISH/CB11—consistency 97.8%, k = 0.91, P < 0.001). Conclusions: There is early involvement of HER2 dysregulation (amplification and protein overexpression) in both gastric (intestinal‐type) and Barrett’s oncogenesis.     

Altered expression of ribonucleotide reductase and role ofM2 gene amplification in hydroxyurea-resistant hamster,mouse, rat,and human cell lines

Five hamster, mouse, and rat cell lines resistant to the cytotoxic effects of hydroxyurea have been characterized. All cell lines contained increased ribonucleotide reductase activity, elevated levels of the M2 component of ribonucleotide reductase as judged by electron paramagnetic resonance spectroscopy, and increased copies of M2 mRNA as determined by Northern blot analysis. Two species of M2 mRNA were detected in rodent cell lines, a high-molecular-weight species of approximately 3.4 kb in hamster and rat cells and about 2.1 kb in mouse cells. The low molecular-weight M2 mRNA was about 1.6 kb in all rodent lines. Northern blot analysis showed that the mRNA for the other component of ribonucleotide reductase, M1, was not markedly elevated in the drug-resistant cells and existed as a single 3.1-kb species. Four of the five resistant lines contained an M2gene amplification as determined by Southern blot analysis, providing direct evidence to support earlier suggestions that hydroxyurea resistance is often accompanied by amplification of a ribonucleotide reductase gene. An increase in gene dosage was detected even in cells exhibiting only modest drug-resistance properties. No evidence for amplification of the M1gene of ribonucleotide reductase was found. In keeping with these observations with drug-resistant rodent lines, a human (HeLa) cell line resistant to hydroxyurea was also found to contain increased levels of two M2 mRNA species (about 3.4 and 1.6 kb) and exhibited M2gene amplification. One hamster cell line resembled the other resistant rodent lines in cellular characteristics but did not show amplification of either the M1or M2gene, providing an example of a drug-resistant mechanism in which an elevation of M2 mRNA has occurred without a concomitant increase in M2gene copy number.     

Notch3 and Jagged2 contribute to gastric cancer development and to glandular differentiation associated with MUC2 and MUC5AC expression

Kang H, An H‐J, Song J‐Y, Kim T‐H, Heo J‐H, Ahn D‐H & Kim G
(2012) Histopathology  61, 576–586 Notch3 and Jagged2 contribute to gastric cancer development and to glandular differentiation associated with MUC2 and MUC5AC expression Aims: Notch signalling plays diverse roles in malignant tumours as well as in normal tissue development. In this study we investigated the expression of Notch signalling pathway genes and their clinicopathological significance in gastric carcinomas. Methods and results: Notch1, Notch3, Jagged1, Jagged2 and Hes1 expression were analysed by quantitative real‐time polymerase chain reaction (qRT–PCR) (n = 81) and immunohistochemistry (n = 103) in gastric carcinomas. MUC2 and MUC5AC expression were also assessed, using immunohistochemistry only. With qRT–PCR, Notch1, Notch3, Jagged1 and Jagged2 expression were increased significantly in tumour compared to normal tissue (P < 0.001, P = 0.002, P = 0.008 and P < 0.001, respectively). Overexpression of Notch3 and Jagged2 was associated with intestinal‐type carcinomas (P = 0.024) and better histological differentiation (P = 0.047), respectively. Immunohistochemistry showed a reverse correlation between MUC2 and Notch3 or Jagged1 (P = 0.033 and P = 0.005, respectively) and between MUC5AC and Jagged1 or Hes1 (P = 0.004 and P = 0.002, respectively). Notch3 and Jagged2 gene overexpression related to a favourable outcome on univariate (P = 0.046 and P = 0.042, respectively) and multivariate (P = 0.045, Notch3) analysis. Conclusions: The expression of Notch3 and Jagged2 is associated not only with gastric cancer development but also with the intestinal/glandular differentiation of gastric carcinoma cells, suggesting a role as a possible favourable prognostic indicator.     

Focal adhesion kinase (FAK) gene amplification and its clinical implications in gastric cancer

Focal adhesion kinase, a nonreceptor tyrosine kinase, is known to be associated with tumor progression in various tumors. Because the clinical implications of focal adhesion kinase overexpression in gastric cancer have been inconsistent, we extended previous studies and evaluated focal adhesion kinase gene amplification as well as its protein expression. Immunohistochemical tissue array analysis showed that focal adhesion kinase immunoreactivity was present in both the cytoplasm and membrane of gastric cancer cells. Diffuse immunoreactivity of focal adhesion kinase protein in cytoplasm or membrane was found in 240 (54%) or 263 (59%) of 444 surgical samples, respectively, and positively correlated with tumor size, depth of tumor infiltration, nodal metastasis, distant metastasis, lymphatic invasion, and venous invasion (P < .001). Regarding focal adhesion kinase gene amplification, fluorescence in situ hybridization analysis showed focal adhesion kinase gene amplification in 34 (8.9%) of 384 gastric cancer specimens, whereas there was no amplification in any case of atrophy, intestinal metaplasia, or adenoma/dysplasia. Focal adhesion kinase gene amplification was positively associated with age (P = .012), tumor size (P = .007), nodal metastasis (P = .021), distant metastasis (P = .029), lymphatic invasion (P = .006), venous invasion (P = .032), and perineural invasion (P = .023). Focal adhesion kinase protein expression and gene amplification were positively correlated with each other, and each of them was found to be an independent poor prognostic factor (P < .01). In conclusion, our results showed that either focal adhesion kinase protein expression or focal adhesion kinase gene amplification was significantly correlated with cancer progression and poor prognosis in gastric cancer. Thus, focal adhesion kinase gene amplification could supplement its protein expression for the diagnosis and treatment of gastric cancer.     

Overexpression of YKL-40 is an independent prognostic marker in gastric cancer

YKL-40 is a growth factor for connective tissue cells and a migration factor for endothelial cells. Elevated serum level of YKL-40 has been associated with poor prognosis in many cancers. However, the status of YKL-40 expression and its clinical/prognostic significance in gastric cancer are unclear. In this study, the expression of YKL-40 was studied by immunohistochemistry in gastric cancer tissue microarray containing 172 primary gastric cancer cases and 70 adjacent nonneoplastic mucosa specimens. The correlations between YKL-40 expression and clinicopathologic features, as well as activation of PI3K/Akt pathways were addressed. Expression of YKL-40 was significantly higher in gastric cancer tissues than that in adjacent nonneoplastic tissues. Overexpression YKL-40 was found in 28.4% of gastric cancers and was significantly associated with tumor invasion (P = .007) and lymph node metastasis (P = .009). For survival study, overexpression of YKL-40 was significantly associated with worse outcome (P = .001). When known clinical variables were added to a multivariate analysis, TNM stage, tumor size, and overexpression of YKL-40 emerged as independent prognostic factors. Further study indicated that the oncogenic function of YKL-40 might be through the activation of Akt pathway. These results suggest that overexpression of YKL-40 is correlated with the aggressive behavior of tumor cells, which could be used as an independent molecular marker for the predicting poor prognosis of patients with gastric cancer.     

Overexpression of transfected human ribonucleotide reductase M2 subunit in human cancer cells enhances their invasive potential

The ribonucleotide reductase (RR) gene has been associated with malignant transformation and metastatic potential. In this report, the significance of the expression of RR mRNA and enzymatic activity to the invasive potential was examined by Boyden chamber invasion assay. Our results suggest that overexpression of RR M2 mRNA and RR enzymatic activity correlates to an increase in cell invasive potential. The drug-induced HURs clone expressed a higher level RR M2 mRNA and enzyme activity which contributes significantly to the 3-fold increase in invasive potential of the cells observed relative to the KB wild-type control. On the contrary, the HUr revertant clone decreased the RR M2 mRNA level and enzymatic activity, concomitantly decreasing their invasive potential. This phenomenon is most likely due to the return of RR to levels comparable to that of the KB wild-type cells. To confirm that this observation was not of a drug-resistance phenotype associated with multiple gene alte rations, the panel of RR transfectants (M1-D transfected M1 subunit cDNA, M2-D transfected M2 subunit cDNA, X-D transfected M1/M2 cDNA) characterized in a previous study were also tested in the invasion assay. The M2-D clone expressed 6-fold higher RR M2 mRNA and RR activity and also demonstrated 6-fold higher invasive potential in vitro than either the parental or vector only transfected cell line (KB-V). The X-D clone demonstrated 3-fold higher M2 mRNA expression and revealed 4-fold higher invasive potential than control cells. The M1-D clone, in contrast, expressed a baseline level of RR M2 mRNA and higher M1 mRNA. In contrast to the X-D and M2-D cells, the invasive potential of M1-D reached an even lower level in the invasive assay than the control. These results, therefore, suggest that RR M2 overexpression plays an important role in a tumor's invasiveness. © Rapid Science 1998     

Overexpression of miR‐17 in gastric cancer is correlated with proliferation‐associated oncogene amplification

The molecular mechanism underlying microRNA (miR)‐17 overexpression has not been clearly evaluated in gastric cancer. We aimed to evaluate the functional roles of miR‐17 in gastric cancer and test its viability as a therapeutic target. We conducted comparative genomic hybridization and expression array analyses on human gastric cancer tissue samples, as well as evaluating the functional roles of miR‐17 in gastric cancer cell lines and transgenic mice. miR‐17 overexpression in gastric cancer patients was associated with copy number gain of proliferation‐associated oncogenes such as MYC, CCNE1, ERBB2, and FGFR2. Copy number gain of MIR17HG gene (13q31.3) was rare, with an overall frequency of 2% in gastric cancers (1 of 51). miR‐17 knockdown suppressed the monolayer and anchorage‐independent growth of FGFR2‐amplified KATO‐III gastric cancer cells. mir‐17–92 TG/TG mice overexpressing the mir‐17–92 cluster under the villin promoter developed spontaneous benign tumors in the intestinal tract (log‐rank P for tumor‐free survival = 0.069). Taken together, miR‐17 overexpression in gastric cancer was rarely associated with MIR17HG gene amplification, but correlated with proliferation‐associated oncogene amplification. Therefore, miR‐17‐targeting approach may benefit patients with gastric cancers harboring proliferation‐associated oncogene amplification.     

Overexpression of leucine‐rich repeat‐containing G protein‐coupled receptor 5 in gastric cancer

Gastric cancer is one of the most common malignancies worldwide and patients with advanced gastric cancer still have poor clinical outcomes. The overexpression of leucine‐rich repeat‐containing G protein‐coupled receptor 5 (LGR5) mRNA in colorectal cancer and its correlation with clinicopathological factors were recently reported by us. In this study, we show LGR5 mRNA overexpression in human gastric cancer specimens by quantitative RT‐PCR and in situ hybridization and assess a correlation with clinicopathological factors. The mean expression of LGR5 mRNA in cancerous tissues was five times higher than that in normal tissue (P = 0.0002). Furthermore, LGR5 mRNA expression show marked variation among cases and significantly increased in cases where lymphatic invasion was present compared with those where it was absent (P = 0.0056). Although the mean expression level of LGR5 was observed to be higher in nodal metastasis and venous invasion positive cases compared to negative cases, a significant difference was not observed. These results suggest that LGR5 can be a biomarker for malignancy in gastric cancer.     

稳定过表达Smac基因对胃癌细胞株凋亡活性的调控作用

目的　探讨稳定过表达Smac基因对胃癌细胞凋亡的影响。方法　脂质体介导Smac基因转染MKN- 45细胞,G418筛选阳性克隆。逆转录聚合酶链反应(RT -PCR)和Western印迹鉴定Smac表达,同时以丝裂霉素作为凋亡诱导因子,采用锥虫蓝活细胞拒染法检测癌细胞体外生长活性,透射电镜、吖啶橙溴化乙啶荧光染色法、末端TdT酶标记技术(TUNEL)观察癌细胞凋亡及比率;Western印迹、比色法检测细胞内caspase- 3表达。结果　所获胃癌亚克隆细胞MKN -45 /Smac的SmacmRNA、蛋白表达水平均显著高于MKN -45(P<0 01)。10μg/ml丝裂霉素作用6 ~24h后,与MKN -45细胞比较,MKN 45 /Smac细胞生长活性减弱10 .0% ~30 8% (P<0 .01),部分MKN- 45 /Smac细胞发生典型的凋亡形态学改变,凋亡率增高21 .2% (P<0. 01 )。丝裂霉素作用后,MKN -45 /Smac细胞内caspase- 3的表达和活性均较MKN- 45细胞显著增强(P<0 .01)。结论　胃癌细胞中Smac基因的过表达,能提高丝裂霉素作用后细胞中caspase 3的表达和活性,显著诱导癌细胞凋亡,为调控胃癌细胞凋亡活性提供了新的途径。     

Induction of hRAD9 is required for G2/M checkpoint signal transduction in gastric cancer cells.

DNA damage triggers the activation of checkpoints that delay cell cycle progression to allow for DNA repair. Loss of G2 checkpoints provides a growth advantage for tumor cells undergoing aberrant mitosis. However, the precise mechanisms of G2 checkpoints acting in gastric cancer are unknown. Here, we analyzed the G2 checkpoint function in two gastric cancer cells, MKN-28 cells containing a mutant p53 gene and MKN-45 cells which have wild-type p53. Two agents damaging DNA, camptothecin (CPT) or ultraviolet light (UV), were utilized to trigger a G2 phase cell cycle checkpoint response in these tumor cells. Both CPT and UV inhibited the growth of MKN-45 cells, whereas they did not affect the growth of MKN-28 cells. CPT induced cell cycle arrest at the G2/M phase and enhanced the expression of human RAD9 (hRAD9) in MKN-45 cells. In addition, hRAD9 showed perinuclear staining and similar localization with Bcl-2 in MKN-45 cells but not in MKN-28 cells after having applied CPT or UV light. These results suggest that besides p53 activity, the induction of hRAD9 is required for G2/M checkpoint signal transduction in gastric cancer cells.     

Increased chemokine receptor IL-17RA expression is associated with poor survival in gastric cancer patients

Background: Previous researchers have identified that the chemokine interleukin-17 (IL-17) was associated with survival time of patients with gastric cancer, but the roles of its receptors (IL-17R) in gastric cancer remain unknown. Our studies were designed to clarify the function of IL-17RA and to explore their potential role in gastric cancer. Materials and methods: The expression of IL-17RA was determined in primary gastric cancer tissues (n=101) using Real-time RT-PCR, immunohistochemistry, and western blotting. To investigate the functional significance of IL-17RA expression, IL-17RA expression and clinical parameters, multivariate survival was analyzed in patients with gastric cancer. Results: IL-17RA was overexpression in gastric cancer tissues compared with adjacent normal tissues (P<0.05). The elevated expression level of IL-17RA was observed correlated significantly with tumor progression (P=0.003), Lymphatic invasion (P=0.019), lymphoid nodal status (P=0.001), distant metastasis (P<0.001) of gastric cancer patients, TNM stage (P=0.0013) and was one of the independent prognostic factors for patient’s overall survival. Conclusions: These results demonstrated that the expression of IL-17RA plays an important role in gastric cancer progression, migration and prognosis of gastric cancer. The IL-17-IL-17RA signaling mechanism may be a potential novel target.     

Overexpression of EpCAM and Trop2 in pituitary adenomas

We sought to investigate the expression of EpCAM and Trop2 in Pituitary adenomas (PAs) and study the correlation of protein expression with invasiveness, proliferation, clinical functioning, recurrence/progression, and some other factors. We investigated the expression of EpCAM and Trop2 in 74 samples of PAs by immunohistochemistry and made correlative analysis of protein overexpression with clinicopathological parameters. Follow-up data was analyzed for recurrence/progression with Kaplan-Meier method and Multivariate Cox regression analysis. Immunohistochemistry results showed that overexpression rates of EpCAM and Trop2 were 51/74 (68.9%) and 43/74 (58.1%), respectively. For both EpCAM and Trop2, PAs with invasiveness showed a higher overexpression rate than PAs without invasiveness (P_EpCAM = 0.001; P_Trop2 = 0.006). Nonfunctional Pituitary adenomas (NFPAs) demonstrated a higher EpCAM overexpression than functional Pituitary adenomas (FPAs) (P = 0.026). Both EpCAM and Trop2 overexpression correlated significantly with expression of proliferation factor Ki-67 (P_EpCAM = 0.011; P_Trop2 = 0.000), but not with gender and age. Follow-up analysis revealed that Trop2 overexpression was a significantly predictive factor for recurrence/progression by means of Kaplan-Meier method d (P = 0.028) and Multivariate Cox regression analysis (P = 0.025). This study reveals that both EpCAM and Trop2 overexpression in PAs correlate significantly with invasiveness and proliferation. EpCAM presents a potential target for differential diagnosis and immunotherapy for NFPAs. Follow-up analysis shows that Trop2 is a predictive factor for recurrence/progression for PAs.     

Fascin expression is related to poor survival in gastric cancer

Fascin is an actin‐binding protein that provides mechanical support and cell motility, and involves cancer cell metastasis. We investigated fascin protein expression in gastric cancer and assessed their relationship with clinicopathologic parameters and survival rates. In addition, we researched galectin‐3 protein expression to study fascin action mechanisms. We performed immunohistochemisty with fascin and galectin‐3 antibodies in 471 gastric carcinomas, using tissue microarrays. Fascin was positive in 14.9% (70/471) of the samples, and fascin expression was related to worse survival rates (P < 0.001), high clinical stage (P < 0.001), high T stage (P < 0.001), nodal metastasis (P < 0.001), lymphovascular invasion (P= 0.001) and the intestinal type of Lauren classification (P= 0.015). Galectin‐3 protein expression was positive in 83.9% (395/471) of the samples and was reversely correlated with fascin protein expression (P= 0.020). Galectin‐3 expression was related to low clinical stage (P < 0.001), but not to survival rates in multivariate analysis. In multivariate analysis, fascin expression was related to worse survival rates (HR = 1.56, P= 0.036), and can be an independent poor prognostic factor in gastric cancer.     

Ribonucleotide reductase M2 does not predict survival in patients with resectable pancreatic adenocarcinoma

Background

Ribonucleotide reductase M2 (RRM2) was associated with pancreatic tumor progression and resistance to gemcitabine. This study aimed to determine if RRM2 protein expression was prognostic in patients with resectable pancreatic adenocarcinoma and predictive of adjuvant gemcitabine benefit.

Methods

117 patients underwent tumor resection for pancreatic adenocarcinoma from 10/1999 to 12/2007. We constructed tissue microarrays from paraffin-embedded tumors and determined RRM2 protein expression using immunohistochemistry and grouped as negative or positive. We estimated overall survival (OS) and progression-free survival (PFS) using the Kaplan-Meier method and examined the prognostic and predictive value of RRM2 expression using Cox proportional hazards model.

Results

RRM2 expression showed no prognostic value in the entire group regarding OS (median OS 30.9 months in RRM2-positive versus 13.7 months in RRM2-negative, P = 0.26) and PFS (median OS 20.6 months in RRM2-positive versus 11.8 months in RRM2-negative, P = 0.46). RRM2 expression did not predict adjuvant gemcitabine benefit in the subgroup of 44 patients who received gemcitabine therapy (median OS 31.2 versus 15.2 months, P = 0.62; median PFS 11.3 versus 14.0 months, P = 0.35). Cox proportional hazards regression showed no prognostic effect of RRM2 expression on OS and PFS in the subgroup of 44 patients. However, the number of positive lymph nodes and perineural invasion were prognostic factors for OS (HR 1.2, P = 0.005) and for PFS (HR 5.5, P = 0.007), respectively.

Conclusion

RRM2 protein expression in pancreatic adenocarcinoma is neither prognostic nor predictive of adjuvant gemcitabine benefit in patients with resectable pancreatic adenocarcinoma.     

Aldehyde dehydrogenase 1 expression is a predictor of poor prognosis in node-positive breast cancers: a long-term follow-up study

Yoshioka T, Umekita Y, Ohi Y, Souda M, Sagara Y, Sagara Y, Sagara Y, Rai Y & Tanimoto A
(2011) Histopathology 58 , 608–616
Aldehyde dehydrogenase 1 expression is a predictor of poor prognosis in node‐positive breast cancers: a long‐term follow‐up study Aims: Aldehyde dehydrogenase 1 (ALDH1) has been identified as a reliable marker of breast cancer stem cells. The aim was to determine the prognostic significance of ALDH1 expression in a long‐term follow‐up study. Methods and results: Immunohistochemical analyses were performed on 257 invasive ductal carcinomas (IDCs), 109 matched lymph node metastases and 190 ductal carcinomas in situ (DCISs), using paraffin‐embedded sections. ALDH1 expression was found in 26% of IDCs, and correlated with larger tumour size (P = 0.007), high histological grade (P < 0.001), HER2 overexpression (P < 0.001) and negative hormone receptor status (P < 0.001). ALDH1 expression was observed in 14% of DCISs but was not correlated with any clinicopathological parameter. The IDC patients were followed up for 7–190 months (median: 120 months), and groups with ALDH1 expression had shorter relapse‐free survival (P = 0.0013) and overall survival (OS) (P = 0.0005) by log‐rank test. By Cox’s multivariate analysis, it had a weak effect on OS (P = 0.047), and its most significant effect on OS was observed in node‐positive groups (P = 0.013). No significant differences in OS stratified by ALDH1 expression status in lymph node metastases were noted. Conclusions: ALDH1 expression in primary cancer is an independent prognostic factor in node‐positive breast cancer patients.