Outcomes of Metastatic and Unresectable Small Bowel Adenocarcinoma in Japan According to the Treatment Strategy: A Nationwide Observational Study.

PURPOSE: Limited information is available regarding the characteristics and outcomes of stage IV small bowel adenocarcinoma (SBA) in Japan. This study examined the clinical and pathological characteristics and outcomes according to the treatment strategies in patients with stage IV SBA. METHODS: This retrospective observational study used the data of patients with jejunal or ileal adenocarcinoma collected by the Small Bowel Malignant Tumor Project of the Japanese Society for Cancer of the Colon and Rectum. Descriptive statistics were expressed as the mean (standard deviation) or median (range). Survival analysis was performed using Kaplan-Meier curves and pairwise log-rank tests. RESULTS: Data from 128 patients were analyzed. The treatment strategies were chemotherapy alone (26 of 128, 20.3%), surgery alone (including palliative surgery; 21 of 128, 16.4%), surgery + chemotherapy (74 of 128, 57.8%), and best supportive care (7 of 128, 5.5%). The median (range) overall survival was 16 (0-125) months overall, and 11 (1-38) months, 8 (0-80) months, 18 (0-125) months, and 0 (0-1) months for the chemotherapy, surgery, surgery + chemotherapy, and best supportive care groups, respectively. Three main categories of chemotherapeutic regimen were used: a combination of fluoropyrimidine and oxaliplatin (F + Ox), fluoropyrimidine and irinotecan (F + Iri), and single-agent fluoropyrimidine. Among patients treated with chemotherapy, the median (range) OS was 16 (1-106) months overall, and 17 (1-87) months, 29 (7-39) months, and 16 (1-106) months in patients treated with fluoropyrimidine, F + Iri, and F + Ox, respectively. CONCLUSION: Patients treated with surgery, chemotherapy, or both had a better prognosis than those who received best supportive care. Among patients who received chemotherapy, survival did not differ according to the chemotherapeutic regimen.

Clinicopathological features and prognosis of primary small bowel adenocarcinoma: a large multicenter analysis of the JSCCR database in Japan.

BACKGROUND: The clinicopathological features and prognosis of primary small bowel adenocarcinoma (PSBA), excluding duodenal cancer, remain undetermined due to its rarity in Japan. METHODS: We analyzed 354 patients with 358 PSBAs, between January 2008 and December 2017, at 44 institutions affiliated with the Japanese Society for Cancer of the Colon and Rectum. RESULTS: The median age was 67 years (218 males, 61.6%). The average tumor size was 49.9 (7-100) mm. PSBA sites consisted of jejunum (66.2%) and ileum (30.4%). A total of 219 patients (61.9%) underwent diagnostic small bowel endoscopy, including single-balloon endoscopy, double-balloon endoscopy, and capsule endoscopy before treatment. Nineteen patients (5.4%) had Lynch syndrome, and 272 patients (76.8%) had symptoms at the initial diagnosis. The rates for stages 0, I, II, III, and IV were 5.4%, 2.5%, 27.1%, 26.0%, and 35.6%, respectively. The 5-year overall survival rates at each stage were 92.3%, 60.0%, 75.9%, 61.4%, and 25.5%, respectively, and the 5-year disease-specific survival (DSS) rates were 100%, 75.0%, 84.1%, 59.3%, and 25.6%, respectively. Patients with the PSBA located in the jejunum, with symptoms at the initial diagnosis or advanced clinical stage had a worse prognosis. However, multivariate analysis using Cox-hazard model revealed that clinical stage was the only significant predictor of DSS for patients with PSBA. CONCLUSIONS: Of the patients with PSBA, 76.8% had symptoms at the initial diagnosis, which were often detected at an advanced stage. Detection during the early stages of PSBA is important to ensure a good prognosis.

Enhanced Clinical Utility of Molecular Budding Signature as a Recurrence Risk Determinant in Stage II and III Colon Cancer Patients.

BACKGROUND: A molecular budding signature (MBS), which consists of seven tumor budding-related genes, was recently presented as a prominent prognostic indicator in colon cancer (CC) using microarray data acquired from frozen specimens. This study aimed to confirm the predictive power of MBS for recurrence risk based on formalin-fixed, paraffin-embedded (FFPE) materials. METHODS: This research utilized the same microarray data from a prior multicenter study using FFPE whole tissue sections, which retrospectively reviewed 232 stage II CC patients without adjuvant chemotherapy and 302 stage III CC patients with adjuvant chemotherapy. All patients underwent upfront curative surgery without neoadjuvant therapy between 2009 and 2012. An MBS score was calculated using the mean of log2 [each signal] of seven genes (MSLN, SLC4A11, WNT11, SCEL, RUNX2, MGAT3, and FOXC1) as described before. RESULTS: The MBS-low group exhibited a better relapse-free survival (RFS) than the MBS-high group in stage II (P = 0.0077) and in stage III CC patients (P = 0.0003). Multivariate analyses revealed that the MBS score was an independent prognostic factor in both stage II (P = 0.0257) and stage III patients (P = 0.0022). Especially among T4, N2, or both (high-risk) stage III patients, the MBS-low group demonstrated markedly better RFS compared with the MBS-high group (P = 0.0013). CONCLUSIONS: This study confirmed the predictive power of the MBS for recurrence risk by employing FFPE materials in stage II/III CC patients.

A multicenter cohort study on mapping of lymph node metastasis for splenic flexural colon cancer.

Aim: There have been no reports of searching for metastases to lymph nodes along the accessory middle colic artery (aMCA). The aim of this study was to investigate the metastasis rate of the aMCA for splenic flexural colon cancer. Methods: Patients with histologically proven colon carcinoma located in the splenic flexure, clinically diagnosed as stage I-III were eligible for this study. Patients were retrospectively and prospectively enrolled. The primary endpoint was frequency of lymph node metastasis to the aMCA (station 222-acc and 223-acc). The secondary endpoint was the frequency of lymph node metastasis to the middle colic artery (MCA) (station 222-lt and 223) and left colic artery (LCA) (station 232 and 253). Results: Between January 2013 and February 2021, a total of 153 consecutive patients were enrolled. The location of the tumor was 58% in the transverse colon and 42% in the descending colon. Lymph node metastases were observed in 49 cases (32%). The presence of aMCA rate was 41.8% (64 cases). The metastasis rates of stations 221, 222-lt, and 223 were 20.0%, 1.6%, and 0%, and stations 231, 232, and 253 were 21.4%, 1.0%, and 0%, respectively. The metastasis rates of stations 222-acc and 223-acc were 6.3% (95% confidence interval: 1.7%-15.2%) and 3.7% (95% confidence interval: 0.1%-19%), respectively. Conclusions: This study identified the distribution of lymph node metastases from splenic flexural colon cancer. If the aMCA is present, this vessel should be targeted for dissection, taking into account the frequency of lymph node metastasis.

Prognostic impact of desmoplastic reaction in esophageal squamous cell carcinoma patients with neoadjuvant therapy.

AIM: This study aimed to examine the prognostic value of desmoplastic reaction (DR) in esophageal squamous cell carcinoma (ESCC), particularly in patients who received neoadjuvant therapy, such as chemotherapy (NAC) or chemoradiotherapy (NACRT). METHOD: In total, 153 patients with pStage II/III ESCC were included in this study. Ninety-one patients received neoadjuvant therapy (NAC, 70; NACRT, 21). Patients were classified according to three DR categories based on the presence of keloid-like collagen and/or myxoid stroma. RESULTS: In total, 50, 50, and 53 patients were classified as having mature, intermediate, and immature DR, respectively. The weighted kappa coefficient was 0.623 in the patients with preoperative treatments and 0.782, in those without. The 5-year disease-specific survival (DSS) rates in patients with intermediate/immature DR was significantly worse than those with mature DR (40.7% vs. 73.3%, p < 0.001). Similarly, the 5-year DSS rate in patients with intermediate/immature DR was significantly worse than those with mature DR in a study of patients who received neoadjuvant therapy (46.7% vs. 71.2%, p = 0.009). Multivariate analysis revealed that DR (hazard ratio [HR]: 3.15, 95% confidence interval [CI] 1.58-6.27, p = 0.001), along with N factors, was an independent risk factor for DSS. Moreover, multivariate analysis of patients who received neoadjuvant therapy revealed only DR (HR: 2.47, 95% CI 1.02-5.96, p = 0.045) as independent risk factors for DSS. CONCLUSION: The DR classification was a valuable prognostic factor not only in the ESCC patients without neoadjuvant therapy but also in those with neoadjuvant therapy.

Prognosis of Pancreatic Cancer Based on Resectability: A Single Center Experience.

Although conversion surgery has increasingly been performed for initially unresectable advanced pancreatic ductal adenocarcinoma (PDAC), the rate of conversion, including that for patients who do not undergo resection, remains unclear. Patients with PDAC who were treated between January 2013 and December 2018 were classified into three groups: resectable (R), borderline resectable (BR), and unresectable (UR). We analyzed patient outcomes, including the rate of surgical resection and survival, in each of these groups. In total, 211 patients (R, 118; BR, 22; UR, 81) were selected. Among them, 117 (99%), 18 (82%), and 15 (19%) patients in the R, BR, and UR groups, respectively, underwent surgical resection. R0 resection rates were 88, 78, and 67%, whereas median overall survival (OS) from treatment initiation were 31, 18, and 11 months (p < 0.0001) in the R, BR, and UR groups, respectively. In patients who underwent surgical resection, relapse-free survival (RFS) and OS were similar among the three groups (R vs. BR vs. UR; median RFS (months), 17 vs. 13 vs. 11, p = 0.249; median OS (months), 31 vs. 26 vs. 32, p = 0.742). Lymph node metastases and incomplete adjuvant chemotherapy were identified as independent prognostic factors for OS. Although the surgical resection rate was low, particularly in the BR and UR groups, the prognosis of patients who underwent surgical resection was similar irrespective of the initial resectability status.

Clinical Impact of Dual Time Point 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Fusion Imaging in Pancreatic Cancer.

We examined the value of preoperative dual time point (DTP) 18F-fluorodeoxyglucose positron emission tomography/computed tomography fusion imaging (FDG PET/CT) as a predictor of early recurrence or the outcomes in patients with pancreatic cancer. Standardized uptake values (SUVs) in DTP FDG PET/CT were performed as preoperative staging. SUVmax1 and SUVmax2 were obtained in 60 min and 120 min, respectively. ΔSUVmax% was defined as (SUVmax2 − SUVmax1)/SUVmax1 × 100. The optimal cut-off values for SUVmax parameters were selected based on tumor relapse within 1 year of surgery. Optimal cut-off values for SUVmax1 and ΔSUVmax% were 7.18 and 24.25, respectively. The combination of SUVmax1 and ΔSUVmax% showed higher specificity and sensitivity, and higher positive and negative predictive values for tumor relapse within 1 year than SUVmax1 alone. Relapse-free survival (RFS) was significantly worse in the subgroups of high SUVmax1 and high ΔSUVmax% (median 7.0 months) than in the other subgroups (p < 0.0001). The multivariate Cox analysis of RFS identified high SUVmax1 and high ΔSUVmax% as independent prognostic factors (p = 0.0060). DTP FDG PET/CT may effectively predict relapse in patients with pancreatic cancer. The combination of SUVmax1 and ΔSUVmax% identified early recurrent patient groups more precisely than SUVmax1 alone.

Optimizing nodal and staging classification in low rectal cancers with lateral node metastasis: multicentre retrospective cohort study.

BACKGROUND: Patients with lateral node metastasis in low rectal cancers have a poor prognosis. However, variability in patient survival in terms of lateral metastatic status has not been thoroughly investigated. This study was conducted to assess the prognostic value of lateral node involvement and to review nodal classification. METHODS: Patients with stage III low rectal cancers who underwent lateral node dissection were retrospectively reviewed. Two cohorts were set: the first one (1995-2006) was selected using a Japanese multi-institutional database and was used for development of a new nodal system, and the second (2007-2013) was collected from referral institutions for validation of findings. Variables correlated with poor prognosis were investigated. Next, a modified classification of lateral-positive nodal cancers was created. Finally, this new classification was compared with TNM and Japanese classification-based systems according to the Akaike information criterion (AIC) and concordance index (c-index). RESULTS: Overall, 742 and 508 patients were selected for cohorts 1 and 2, respectively. Based on the analyses on cohort 1, patients with two or more lateral metastatic nodes partially spreading into regions outside of internal iliac area exhibited poor prognosis; accordingly, a modified N classification was created, where TNM-N1 and N2a cancers with this feature were upgraded, respectively, to N2a and N2b. The modified N classification yielded the most favourable indices (AIC = 2661.08; c-index = 0.6477) compared with the TNM (AIC = 2662.36; c-index = 0.6457) and Japanese classification-based systems (AIC = 2684.06; c-index = 0.6302). All findings were confirmed by analysing cohort 2. CONCLUSION: A modified nodal system is proposed to account for the significance of lateral node metastasis.

Three-dimensional imaging of intramural perineural invasion in colorectal cancer: Three-dimensional reconstruction approach with multiple immunohistochemically stained sections.

Perineural invasion (PNI) at Auerbach's plexus in colorectal cancer (CRC), known as intramural PNI, is associated with adverse prognostic outcomes. This study aimed to characterize the three-dimensional (3D) architecture of CRC with intramural PNI and to evaluate the morphological features of tumor invasion around nerve tissue. Serial tissue sections from two cases of CRC were stained with cytokeratin AE1/AE3 and an anti-S-100 protein antibody. 3D models were reconstructed by scanning the virtual slides. In one case, intramural PNI was observed at the horizontal invasive front. The 3D reconstruction model showed tumor cells that appeared to infiltrate along the nervous meshwork, the structure of which was preserved. In the other case, intramural PNI was observed both at and behind the horizontal invasive front, and the 3D reconstruction model showed that the tumor cells appeared to be involved with nerve cells at the focal part of the horizontal invasive front. However, the nervous meshwork structure was not well identified in cancer-involved areas. This is the first study to characterize the 3D structure of tumor invasion around nerve tissue in CRC, demonstrating the morphological features of intramural PNI in CRC.

Cancer-associated fibroblasts at the unfavorable desmoplastic stroma promote colorectal cancer aggressiveness: Potential role of ADAM9.

The tumor microenvironment plays a key role in cancer aggressiveness. Desmoplastic reaction (DR), morphologically classified as Mature, Intermediate and Immature types, has previously been shown to be highly prognostic in colorectal cancer (CRC) and it consists to a large extent of cancer-associated fibroblasts (CAFs). The aim of our study was to characterize the molecular background of DR and understand the effects of CAFs in tumor aggressiveness. The prognostic significance of DR was initially examined in 1497 patients. Then CAFs originating from patient tissues with different DR types were isolated and their impact on tumor growth was examined both in vitro and in vivo. DR was shown to be highly prognostic, with patients within the Immature DR group conferring the worst relapse-free survival. The conditioned media of CAFs from tumor with Immature-type DR (CAFsImmature ) significantly increased proliferation and migration of CRC cell lines and growth of CRC-derived organoids compared to that of CAFs from Mature-type DR (CAFsMature ). Subcutaneous or orthotopic implantation of CRC cells together with CAFsImmature in mice significantly promoted tumor growth and dissemination compared to implantation with CAFsMature . Systematic examination of the expression of "a disintegrin and metalloproteinases" (ADAMs) in CAFs isolated from CRC tissues showed that the secreted isoform of ADAM9 (ADAM9s) was significantly higher in CAFsImmature than in CAFsMature . Knockdown of ADAM9s in CAFsImmature abrogated the promoting effects on CRC cell proliferation and migration. CAFs-derived ADAM9s is implicated in deteriorating survival in CRC patients with Immature-type DR by increasing tumor cell proliferation and dissemination.

Proposal for a tumor budding predictive score derived from endoscopic biopsy samples in colorectal cancer.

BACKGROUND: In colorectal cancer, tumor budding is highlighted as both a prognostic indicator and a predictor of chemosensitivity. However, tumor budding has a serious drawback because of unattainable preoperative assessment, thereby, making it not applicable to decision-making on treatment strategies. Recently, high expressions of seven genes (i.e., MSLN, SLC4A11, WNT11, SCEL, RUNX2, MGAT3, and FOXC1) were shown to be associated with high-budding colorectal cancers. This study aimed to propose a budding prediction system using selected RNAs extracted from biopsy specimens. METHODS: The RNA expression levels in 86 surgically resected samples and in 104 samples obtained by colonoscopy before surgery were investigated. RESULTS: The tumor surface expressions of four exclusive genes (i.e., MSLN, SLC4A11, SCEL, and MGAT3) were correlated with the tumor budding grade. Subsequently, the logit P value calculated by multiple logistic regression analysis using the four surface gene expressions was set as the following budding predictive score: Logit (P) = - 0.55 + 0.27*MSLN + 0.16*SLC4A11 + 0.06*MGAT3 + 0.21*SCEL. The effectiveness of the model using colorectal cancer biopsy samples was well corroborated prospectively. CONCLUSION: The budding predictive score that we developed using endoscopic biopsy specimens was clarified to have a high potential for preoperative use.

How has the COVID-19 pandemic affected gastrointestinal surgery for malignancies and surgical infections?

The coronavirus disease 2019 (COVID-19) pandemic has affected infection control and prevention measures. We investigated the impact of the COVID-19 pandemic on postoperative infections and infection control measures in patients underwent gastrointestinal surgery for malignancies. We retrospectively evaluated changes in clinicopathological features, frequency of alcohol-based hand sanitizer use, frequency of postoperative complications, and microbial findings among our patients in February-May in 2019 (Control group) and 2020 (Pandemic group), respectively. Surgical resection in pathological stage III or IV patients was more frequently performed in the Pandemic group than in the Control group (P = 0.02). The total length of hospitalization and preoperative hospitalization was significantly shorter in the Pandemic group (P = 0.01 and P = 0.008, respectively). During the pandemic, hand sanitizer was used by a patients for an average of 14.9±3.0 times/day during the pandemic as opposed to 9.6±3.0 times/day in 2019 (p<0.0001). Superficial surgical site infection and infectious colitis occurred less frequently during the pandemic (P = 0.04 and P = 0.0002, respectively). In Pandemic group, Enterobacter, Haemophilus, and Candida were significantly decreased in microbiological cultures (P < 0.05, P < 0.05, P = 0.02, respectively) compared with Control group. Furthermore, a significant decrease in Streptococcus from drainage cultures was observed in the Pandemic group (P < 0.05). During the COVID-19 pandemic, a decrease in nosocomial infections was observed in the presence of an increase in alcohol-based hand sanitizer use.

Evaluation of a 55-gene classifier as a prognostic biomarker for adjuvant chemotherapy in stage III colon cancer patients.

BACKGROUND: Adjuvant chemotherapy reduces the risk of recurrence of stage III colon cancer (CC). However, more effective prognostic and predictive biomarkers are needed for better treatment stratification of affected patients. Here, we constructed a 55-gene classifier (55GC) and investigated its utility for classifying patients with stage III CC. METHODS: We retrospectively identified patients aged 20-79 years, with stage III CC, who received adjuvant chemotherapy with or without oxaliplatin, between the years 2009 and 2012. RESULTS: Among 938 eligible patients, 203 and 201 patients who received adjuvant chemotherapy with and without oxaliplatin, respectively, were selected by propensity score matching. Of these, 95 patients from each group were analyzed, and their 5-year relapse-free survival (RFS) rates with and without oxaliplatin were 73.7 and 77.1%, respectively. The hazard ratios for 5-year RFS following adjuvant chemotherapy (fluoropyrimidine), with and without oxaliplatin, were 1.241 (95% CI, 0.465-3.308; P = 0.67) and 0.791 (95% CI, 0.329-1.901; P = 0.60), respectively. Stratification using the 55GC revealed that 52 (27.3%), 78 (41.1%), and 60 (31.6%) patients had microsatellite instability (MSI)-like, chromosomal instability (CIN)-like, and stromal subtypes, respectively. The 5-year RFS rates were 84.3 and 72.0% in patients treated with and without oxaliplatin, respectively, for the MSI-like subtype (HR, 0.495; 95% CI, 0.145-1.692; P = 0.25). No differences in RFS rates were noted in the CIN-like or stromal subtypes. Stratification by cancer sidedness for each subtype showed improved RFS only in patients with left-sided primary cancer treated with oxaliplatin for the MSI-like subtype (P = 0.007). The 5-year RFS rates of the MSI-like subtype in left-sided cancer patients were 100 and 53.9% with and without oxaliplatin, respectively. CONCLUSIONS: Subclassification using 55GC and tumor sidedness revealed increased RFS in patients within the MSI-like subtype with stage III left-sided CC treated with fluoropyrimidine and oxaliplatin compared to those treated without oxaliplatin. However, the predictive power of 55GC subtyping alone did not reach statistical significance in this cohort, warranting larger prospective studies. TRIAL REGISTRATION: The study protocol was registered in the University Hospital Medical Education Network (UMIN) clinical trial registry (UMIN study ID: 000023879 ).

Co-expression of mesothelin and CA125/MUC16 is a prognostic factor for breast cancer, especially in luminal-type breast cancer patients.

The expression of mesothelin correlates with a poor prognosis in patients with breast cancer. Since mesothelin plays a role in cancer metastasis in association with CA125, we herein examined the expression of mesothelin and CA125, and the clinicopathological meaning and prognosis of the co-expression of mesothelin and CA125 in breast cancer. Our results showed that among 478 patients, mesothelin and CA125 were co-expressed in 48 (10 %), mesothelin only in 75 (16 %), CA125 only in 217 (45 %), and neither in 234 (49 %). A high correlation was observed between the expression of mesothelin and CA125 (P =0.0004). The co-expression of mesothelin and CA125 correlated with poor patient relapse-free survival (RFS) (P = 0.0001) and was identified as an independent predictor of RFS by Cox's multivariate analysis. In conclusion, this is the first to report the prognostic significance of the co-expression of mesothelin and CA125 in breast cancer. The co-expression of mesothelin and CA125 may be clinically useful for prognostication after surgical therapy in patients with breast cancer.

Mesothelin Expression is Correlated with Chemoresistance in Stage IV Colorectal Cancer.

BACKGROUND: Mesothelin (MSLN) is a cell-surface glycoprotein present on mesothelial cells; its expression in several epithelial cancers generally portends an unfavorable prognosis. We investigated MSLN as a surrogate chemopredictive biomarker and examined the impact of MSLN expression in stage IV colorectal cancer (CRC). METHODS: We recruited 254 patients with CRC who received systemic chemotherapy following primary tumor resection between 2000 and 2019. Resected specimens were immunostained for MSLN and stratified by MSLN expression. The associations of tumor MSLN expression with tumor response in metastatic lesions and survival were evaluated. RESULTS: Of the 247 patients with stage IV CRC, 41 (16.1%) and 213 (83.9%) had high and low MSLN expression, respectively. Based on the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria, the investigator-assessed objective response rate was 22.0% in the high MSLN expression group and 45.5% in the low MSLN expression group (p = 0.0050). The disease control rates in these groups were 65.9% and 85.9%, respectively (p = 0.00019). In the patients with high MSLN expression, the conversion rate among those with initially unresectable metastases was 0% versus 14% in the patients with low MSLN expression (p = 0.0053). The median overall survival (OS) was 1.5 years (95% confidence interval [CI] 1.1-2.8) in the high MSLN expression group versus 2.6 years (95% CI 2.2-3.0) in the low MSLN expression group. The 3-year OS rates in these groups were 23.5 and 41.5%, respectively (p = 0.0120). CONCLUSIONS: High MSLN expression is correlated with chemoresistance and poor prognoses in stage IV CRC.

Erratum: Recurrent cholangiocarcinoma with long-term survival by multimodal treatment: A case report.

[This corrects the article DOI: 10.3892/mco.2021.2234.].

Different role of MSLN and CA125 co-expression as a prognostic predictor between perihilar and distal bile duct carcinoma.

Recent studies have suggested that the interaction of mesothelin (MSLN) and cancer antigen 125 (CA125) enhances tumor metastases. The aim of the present study was to clarify the impact of MSLN and CA125 co-expression on the prognosis of patients with extrahepatic bile duct carcinoma (BDC). Tissue samples from patients who underwent surgical resection between 2007 and 2015 for perihilar or distal BDC were immunohistochemically examined. The expression levels of MSLN and CA125 in tumor cells were analyzed. The expression in <50% and ≥50% of the total tumor cells were defined as low- and high-level expression, respectively. Tissue samples were obtained from 31 patients with perihilar BDC and 43 patients with distal BDC. Lymph node metastases were associated with MSLN and CA125 co-expression in patients with perihilar BDC (P=0.002), while there was no association between lymph node metastasis and co-expression in patients with distal BDC (P=0.362). MSLN and CA125 co-expression was associated with a worse overall survival rate in patients with perihilar BDC (5-year overall survival rate, co-expression positive vs. negative, 24 vs. 63%; P=0.038). To the best of our knowledge, the present study is the first to report an association between co-expression of MSLN and CA125 with a poor prognosis in patients with perihilar BDC. The current findings suggested that the significance of co-expression differed according to the BDC location.