Expression of Cartilage Oligomeric Matrix Protein in colorectal cancer is an adverse prognostic factor and correlates negatively with infiltrating immune cells and PD-L1 expression

Introduction

Cartilage Oligomeric Matrix Protein (COMP) is an oncogenic protein that has been associated with a decrease in infiltrating T-cells in periampullary adenocarcinoma. This study aimed to investigate whether this is also the case for colorectal cancer (CRC) and to evaluate the relationship between COMP expression and clinopathological features.

Methods

Immunohistochemistry was used to determine the expression levels of COMP in tumor cells and stroma in primary tumors from a cohort of 537 CRC patients. The expression of immune cell markers, including CD3+, CD8+, FoxP3+, CD68+, CD56+, CD163+, and PD-L1, was evaluated previously. Tumor fibrosis was assessed by Sirius Red staining and evaluation of collagen fiber organization.

Results

COMP expression correlated positively with TNM-stage and grade of differentiation. Patients with CRC expressing high levels of COMP had significantly shorter OS than those with low COMP expression (p<0.0001), and fewer infiltrating T-cells were detected in tumors with high COMP expression. Additionally, a negative correlation was identified between the expression of COMP and PD-L1 on both tumor cells and immune cells. Cox regression analysis showed that tumors expressing high levels of COMP had significantly shorter OS, independent of all evaluated immune cell markers. Tumor fibrosis was correlated with high expression of COMP in the stroma (p<0.0001), and tumors with high levels of COMP expression and denser fibrosis displayed more sparse immune cell infiltration.

Discussion

The results suggest that COMP expression in CRC may exert an immune regulatory effect by increasing dense fibrosis and decreasing immune cell infiltration. These findings support the notion that COMP is an important factor in the development and progression of CRC.

A Prospective Diet-Wide Association Study for Risk of Colorectal Cancer in EPIC

BACKGROUND & AIMS

Evidence regarding the association of dietary exposures with colorectal cancer (CRC) risk is not consistent with a few exceptions. Therefore, we conducted a diet-wide association study (DWAS) in the European Prospective Investigation into Cancer and Nutrition (EPIC) to evaluate the associations between several dietary exposures with CRC risk.

METHODS

The association of 92 food and nutrient intakes with CRC risk was assessed in 386,792 participants, 5069 of whom developed incident CRC. Correction for multiple comparisons was performed using the false discovery rate, and emerging associations were examined in the Netherlands Cohort Study (NLCS). Multiplicative gene-nutrient interactions were also tested in EPIC based on known CRC-associated loci.

RESULTS

In EPIC, alcohol, liquor/spirits, wine, beer/cider, soft drinks, and pork were positively associated with CRC, whereas milk, cheese, calcium, phosphorus, magnesium, potassium, riboflavin, vitamin B6, beta carotene, fruit, fiber, nonwhite bread, banana, and total protein intakes were inversely associated. Of these 20 associations, 13 were replicated in the NLCS, for which a meta-analysis was performed, namely alcohol (summary hazard ratio [HR] per 1-SD increment in intake: 1.07; 95% confidence interval [CI], 1.04-1.09), liquor/spirits (HR per 1-SD increment in intake, 1.04; 95% CI, 1.02-1.06), wine (HR per 1-SD increment in intake, 1.04; 95% CI, 1.02-1.07), beer/cider (HR per 1-SD increment in intake, 1.06; 95% CI, 1.04-1.08), milk (HR per 1-SD increment in intake, 0.95; 95% CI, 0.93-0.98), cheese (HR per 1-SD increment in intake, 0.96; 95% CI, 0.94-0.99), calcium (HR per 1-SD increment in intake, 0.93; 95% CI, 0.90-0.95), phosphorus (HR per 1-SD increment in intake, 0.92; 95% CI, 0.90-0.95), magnesium (HR per 1-SD increment in intake, 0.95; 95% CI, 0.92-0.98), potassium (HR per 1-SD increment in intake, 0.96; 95% CI, 0.94-0.99), riboflavin (HR per 1-SD increment in intake, 0.94; 95% CI, 0.92-0.97), beta carotene (HR per 1-SD increment in intake, 0.96; 95% CI, 0.93-0.98), and total protein (HR per 1-SD increment in intake, 0.94; 95% CI, 0.92-0.97). None of the gene-nutrient interactions were significant after adjustment for multiple comparisons.

CONCLUSIONS

Our findings confirm a positive association for alcohol and an inverse association for dairy products and calcium with CRC risk, and also suggest a lower risk at higher dietary intakes of phosphorus, magnesium, potassium, riboflavin, beta carotene, and total protein.

Development and validation of a lifestyle-based model for colorectal cancer risk prediction: the LiFeCRC score

BACKGROUND

Nutrition and lifestyle have been long established as risk factors for colorectal cancer (CRC). Modifiable lifestyle behaviours bear potential to minimize long-term CRC risk; however, translation of lifestyle information into individualized CRC risk assessment has not been implemented. Lifestyle-based risk models may aid the identification of high-risk individuals, guide referral to screening and motivate behaviour change. We therefore developed and validated a lifestyle-based CRC risk prediction algorithm in an asymptomatic European population.

METHODS

The model was based on data from 255,482 participants in the European Prospective Investigation into Cancer and Nutrition (EPIC) study aged 19 to 70 years who were free of cancer at study baseline (1992-2000) and were followed up to 31 September 2010. The model was validated in a sample comprising 74,403 participants selected among five EPIC centres. Over a median follow-up time of 15 years, there were 3645 and 981 colorectal cancer cases in the derivation and validation samples, respectively. Variable selection algorithms in Cox proportional hazard regression and random survival forest (RSF) were used to identify the best predictors among plausible predictor variables. Measures of discrimination and calibration were calculated in derivation and validation samples. To facilitate model communication, a nomogram and a web-based application were developed.

RESULTS

The final selection model included age, waist circumference, height, smoking, alcohol consumption, physical activity, vegetables, dairy products, processed meat, and sugar and confectionary. The risk score demonstrated good discrimination overall and in sex-specific models. Harrell's C-index was 0.710 in the derivation cohort and 0.714 in the validation cohort. The model was well calibrated and showed strong agreement between predicted and observed risk. Random survival forest analysis suggested high model robustness. Beyond age, lifestyle data led to improved model performance overall (continuous net reclassification improvement = 0.307 (95% CI 0.264-0.352)), and especially for young individuals below 45 years (continuous net reclassification improvement = 0.364 (95% CI 0.084-0.575)).

CONCLUSIONS

LiFeCRC score based on age and lifestyle data accurately identifies individuals at risk for incident colorectal cancer in European populations and could contribute to improved prevention through motivating lifestyle change at an individual level.

Pre-diagnostic anthropometry, sex, and risk of colorectal cancer according to tumor immune cell composition

Obesity is a well-established risk factor for colorectal cancer (CRC), but the association with the tumor microenvironment has been sparsely described. Herein, we examined the relationship between pre-diagnostic anthropometry and CRC risk according to tumor immune cell composition, with particular reference to potential sex differences.

The density of different immune cell subsets was assessed by immunohistochemistry in tissue microarrays with tumors from 584 incident CRC cases in a prospective, population-based cohort (n = 28098). Multivariable Cox regression models, adjusted for age, smoking, alcohol intake, and educational level, were applied to calculate risk of immune marker-defined CRC in relation to quartiles of pre-diagnostic height, weight, body mass index (BMI), waist and hip circumferences, waist-hip ratio (WHR), and body fat percentage (BFP).

Obesity was all over significantly associated with risk of CRC with low density of FoxP3⁺ T cells and low programmed cell-death protein 1 (PD-L1) expression on tumor cells, but with high density of CD8⁺ T cells and CD20⁺ B cells. In women, obesity was significantly associated with risk of PD-L1 high tumors (p= 0.009 for weight, p= 0.039 for BMI). Contrastingly, in men, obesity defined by all anthropometric factors was significantly associated with PD-L1 low tumors (p= 0.005 for weight, p = 0.002 for BMI, p<0.001 for waist, p= 0.011 for hip, p<0.001 for WHR, and p= 0.004 for BFP).

In summary, obesity appears to influence the immune landscape of CRC, possibly in a sex-dependent manner. Thus, anthropometry and sex may be important factors to take into account when assessing the prognostic or predictive value of relevant complementary immune biomarkers.

Heterogeneity of Colorectal Cancer Risk Factors by Anatomical Subsite in 10 European Countries: A Multinational Cohort Study

BACKGROUND & AIMS

Colorectal cancer located at different anatomical subsites may have distinct etiologies and risk factors. Previous studies that have examined this hypothesis have yielded inconsistent results, possibly because most studies have been of insufficient size to identify heterogeneous associations with precision.

METHODS

In the European Prospective Investigation into Cancer and Nutrition study, we used multivariable joint Cox proportional hazards models, which accounted for tumors at different anatomical sites (proximal colon, distal colon, and rectum) as competing risks, to examine the relationships between 14 established/suspected lifestyle, anthropometric, and reproductive/menstrual risk factors with colorectal cancer risk. Heterogeneity across sites was tested using Wald tests.

RESULTS

After a median of 14.9 years of follow-up of 521,330 men and women, 6291 colorectal cancer cases occurred. Physical activity was related inversely to proximal colon and distal colon cancer, but not to rectal cancer (P heterogeneity = .03). Height was associated positively with proximal and distal colon cancer only, but not rectal cancer (P heterogeneity = .0001). For men, but not women, heterogeneous relationships were observed for body mass index (P heterogeneity = .008) and waist circumference (P heterogeneity = .03), with weaker positive associations found for rectal cancer, compared with proximal and distal colon cancer. Current smoking was associated with a greater risk of rectal and proximal colon cancer, but not distal colon cancer (P heterogeneity = .05). No heterogeneity by anatomical site was found for alcohol consumption, diabetes, nonsteroidal anti-inflammatory drug use, and reproductive/menstrual factors.

CONCLUSIONS

The relationships between physical activity, anthropometry, and smoking with colorectal cancer risk differed by subsite, supporting the hypothesis that tumors in different anatomical regions may have distinct etiologies.

Expression of programmed cell death protein 1 (PD-1) and its ligand PD-L1 in colorectal cancer: Relationship with sidedness and prognosis

Expression of programmed cell death protein 1 (PD-1) and its ligand PD-L1 has been demonstrated to confer a prognostic value in colorectal cancer (CRC), but no studies have investigated whether this association differs according to tumour location. In this study, immunohistochemical expression of PD-1 and PD-L1 was analysed in tissue microarrays with primary tumours from 557 incident CRC cases from a prospective population-based cohort. Univariable and multivariable Cox regression analyses, adjusted for age, sex, TNM stage, differentiation grade and vascular invasion, were applied to determine the impact of biomarker expression on 5-year overall survival (OS), in the entire cohort and in subgroup analysis of right colon, left colon, and rectum. High PD-L1 expression on tumour-infiltrating immune cells was an independent factor of a prolonged OS in the entire cohort (hazard ratio [HR] = 0.49; 95% confidence interval [CI] CI 0.35 – 0.68), and in tumours of the right colon (HR = 0.43; 95% CI 0.25 – 0.74) and the left colon (HR = 0.28; 95% CI 0.13 – 0.61), but not in rectal cancer. Tumour-specific PD-L1-expression was not prognostic, neither in the full cohort nor according to tumour location. High immune cell-specific PD-1 expression was associated with a prolonged OS in the entire cohort and in tumours of the right colon, but not in the left colon or rectum, and only in univariable analysis. In conclusion, these results demonstrate that immune cell-specific PD-L1 and PD-1 expression is prognostic in a site-dependent manner, whereas tumour-specific PD-L1-expression is not prognostic in CRC.

Prognostic impact of PD-L1 and PD-1 expression by primary tumor location in colorectal cancer

628

Background: A plethora of studies report abundant expression of programmed death-ligand 1 (PD-L1) on tumors to be associated with poor outcome in several cancer forms, whereas immune cell-specific expression of PD-L1 has been associated with improved prognosis in colorectal cancer. However, none of these studies have investigated the association with prognosis according to primary tumor location. This study aimed to investigate the clinicopathological correlates and prognostic impact of PD-L1 and its receptor PD-1 in colorectal cancer, with particular reference to the anatomical subsite of the primary tumor. Methods: Immunohistochemical expression of PD-L1 and PD-1 was analysed in tissue microarrays with tumors from 557 incident cases of CRC from a prospective population-based cohort. Kaplan-Meier and Cox regression analyses were applied to determine the impact of biomarker expression on 5-year overall survival (OS), in the entire cohort and in subgroup analysis of right colon, left colon, and rectum. Results: High PD-L1 expression on tumor-infiltrating immune cells correlated significantly with an improved 5-year OS in univariable and multivariable analysis, adjusted for age, sex, TNM stage, differentiation grade, and vascular invasion, in the full cohort (HR = 0.49; 95 % CI 0.35-0.68), and in primary tumors of the right (HR = 0.43; 95 % CI 0.25-0.74) and the left colon (HR = 0.28; 95 % CI 0.13-0.61), but not in rectal cancer. High tumor-specific PD-L1-expression was not significantly associated with prognosis in neither the full cohort nor according to primary tumor location. High expression of PD-1 on tumor-infiltrating immune cells was significantly associated with an improved 5-year overall survival in the entire cohort (HR = 0.42; 95 % CI 0.21-0.87), but not in subsite analysis according to primary tumor location. Conclusions: This study is, to the best of our knowledge, the first to investigate the prognostic impact of PD-L1 and PD-1 expression according to primary tumor site in colorectal cancer. Dense infiltration of PD-L1+ immune cells was found to be an independent favorable prognostic factor in primary tumors of the right and left colon, but not in the rectum.

The clinical impact of tumour-infiltrating lymphocytes in colorectal cancer differs by anatomical subsite: A cohort study

Accumulating evidence demonstrates an association between dense infiltration of lymphocytes and prognosis in colorectal cancer (CRC), but whether this prognostic impact differs by tumour location remains unknown. This study investigated the prognostic impact of cytotoxic and regulatory T cells in CRC, with particular reference to the anatomical subsite of the primary tumour. The density of CD3⁺ , CD8⁺ and FoxP3⁺ tumour-infiltrating T cells was calculated in tissue microarrays with tumours from 557 incident CRC cases from a prospective population-based cohort. Kaplan-Meier and Cox regression analyses were applied to determine the impact of high and low lymphocyte density on 5-year overall survival, in subgroup analysis of right colon, left colon and rectum. High CD8⁺ cell density was a favourable prognostic factor for patients with right-sided colon tumours (hazard ratio [HR]=0.53, 95% confidence interval [CI] 0.29-0.95), independent of age, sex, TNM stage, differentiation grade and vascular invasion, with a significant prognostic interaction between CD8⁺ cells and right-sidedness (p = 0.031). High FoxP3⁺ cell density was an independent favourable prognostic factor only in patients with rectal tumours (HR = 0.54, 95% CI 0.30-0.99), and CD3⁺ cell density was an independent favourable prognostic factor for tumours in the right colon and rectum, but there was no significant prognostic interaction between CD3⁺ or FoxP3⁺ cells and sidedness. These results demonstrate that the prognostic impact of tumour-infiltrating lymphocytes in CRC differs by primary tumour site, further indicating that tumour location may be an important factor to take into consideration in therapeutic decisions, including eligibility for immunotherapy.

The prognostic impact of tumor-infiltrating lymphocytes in colorectal cancer differs by anatomical subsite

47

Background: Several studies report dense infiltration of tumour-infiltrating T cells and natural killer cells to be associated with an improved prognosis in colorectal cancer (CRC); but whether these associations differ by tumour location remain unknown. This study investigated the prognostic impact of immune cell infiltration in CRC, with particular reference to the anatomical subsite of the primary tumour. Methods: Immunohistochemical expression of CD3, CD8, FoxP3, and CD56 was analysed in tissue microarrays with tumours from 557 incident CRC cases from a prospective population-based cohort. Kaplan-Meier and Cox regression analyses were applied to determine the impact of biomarker expression on 5-year overall survival (OS), in the entire cohort and in subgroup analysis of right colon, left colon, and rectum. Results: In the entire cohort, dense infiltration of all the investigated immune cells correlated significantly with an improved 5-year OS in both univariable and multivariable analysis, adjusted for age, TNM stage, differentiation grade, and vascular invasion. Dense infiltration of CD3+ and CD8+ cells were independent favourable prognostic factors for tumours in the right colon (hazard ratio [HR] = 0.53, 95 % confidence interval [CI] 0.29-0.95 and HR = 0.35, 95% CI 0.19-0.65, respectively), but not in the left colon or rectum. When microsatellite instability status was included in the adjusted model, only CD8+ cells remained an independent favourable prognostic factor in right-sided tumours. Dense infiltration of FoxP3+ cells was an independent favourable prognostic factor for tumours in the rectum (HR = 0.54, 95% CI 0.30-0.99), but not in the right or left colon. Infiltration of CD56+ cells did not carry any independent prognostic impact after stratifying for primary tumour site. Conclusions: The results from this study demonstrate that the prognostic impact of certain T cell subsets in CRC differs by primary tumour site, being most evident in right-sided tumours. These findings indicate that tumour location may be an important factor to take into consideration in therapeutic decisions, including eligibility for immunotherapy.

The difference in prognostic value of tumour-infiltrating T cells according to adjuvant chemotherapy in radiochemonaïve gastroesophageal cancer

41

Background: Several studies have demonstrated a beneficial prognostic impact of tumour-infiltrating lymphocytes (TILs) in oesophageal and gastric adenocarcinoma, but whether this association differs according to adjuvant chemotherapy has not been reported. Herein, we examined the prognostic impact of different TIL subsets according to adjuvant chemotherapy in these cancer types. Methods: Immunohistochemistry was applied to assess the density of T cells (CD3+, CD8+, FoxP3+) and natural killer (NK)/T cells (CD56+) in radiochemonaïve tumors from a consecutive cohort of 174 patients with resected oesophageal or gastric adenocarcinoma. Cox proportional hazard’s modelling was applied to examine the impact of the investigated markers on time to recurrence (TTR) and overall survival (OS). Results: Dense infiltration of CD3+, CD8+, and FoxP3+ cells were all associated with a significantly prolonged TTR in univariable Cox regression analysis (hazard ratio[HR] = 0.57; 95% confidence interval [CI] 0.37-0.89; HR = 0.31, 95% CI 0.13-0.77, and HR = 0.44, 95% CI 0.28-0.68). This association remained significant for CD8+ and FoxP3+ cells in multivariable analysis, adjusted for age, tumour location, TNM stage, differentiation grade, resection margin and adjuvant chemotherapy ( HR = 0.30, 95% CI 0.11-0.77, and HR = 0.52, 95% CI 0.32-0.84), and borderline significant for CD3+ cells (HR = 0.63, 95% CI 0.39-1.02). Similar associations were observed for all markers in relation to OS. Notably, analysis in strata according to adjuvant chemotherapy revealed that none of the investigated lymphocyte subsets carried prognostic information in patients having received treatment (n = 13; 7.5%), with a significant treatment interaction between CD3+ and CD8+ cells and adjuvant chemotherapy (pinteraction0.035 and 0.021). Conclusions: These results confirm the prognostic value of a high density of TILs in gastroesophageal adenocarcinoma, but also indicate that adjuvant chemotherapy is only beneficial in patients with tumors displaying a low density of TILs. These results are of potential clinical relevance and need to be confirmed in additional, preferentially randomized, studies.

Prognostic impact of tumour-associated B cells and plasma cells in oesophageal and gastric adenocarcinoma

BACKGROUND

While it is well established that the cell-mediated immune response plays an important role in cancer progression and spread, the role of the humoral immune response in this regard has been less studied. According to the existing literature, dense infiltration of B cells or plasma cells appears to correlate mainly with an improved prognosis in several types of cancer, but their prognostic impact in oesophageal and gastric cancer has not yet been described.

METHODS

Immunohistochemistry was applied on tissue microarrays (TMA) to assess the stromal density of B cells (CD20+) and plasma cells [CD138+ or immunoglobulin kappa C (IGKC+)] in chemo-/radiotherapy-naive tumours from a consecutive cohort of 174 patients with resected oesophageal or gastric adenocarcinoma. Cox proportional hazard's modelling was applied to examine the impact of the investigated markers on overall survival (OS) and time to recurrence (TTR).

RESULTS

In curatively treated patients with oesophageal adenocarcinoma, high expression of IGKC was an independent predictor of a prolonged OS [hazard ratio (HR) 0.10; 95% confidence interval (CI), 0.02-0.57], and TTR (HR 0.15; 95% CI, 0.03-0.71). In curatively treated patients with gastric adenocarcinoma, high expression of IGKC independently predicted a prolonged OS (HR 0.46; 95% CI, 0.24-0.87) and TTR (HR 0.46; 95% CI, 0.21-0.98). Expression of CD20 was not prognostic, and CD138 expression was only prognostic in unadjusted analysis of TTR in gastric cancer.

CONCLUSIONS

These results demonstrate, for the first time, that abundant infiltration of IGKC+ plasma cells independently predicts a prolonged survival in both oesophageal and gastric cancer.

Prognostic impact of tumour-associated B cells and plasma cells in epithelial ovarian cancer

BACKGROUND

The critical role of the immune system in controlling cancer progression has become evident and immune modulatory therapy is now approved for clinical use. However, while the majority of studies on the inflammatory tumour microenvironment have focused on the cellular immune response, in particular the prognostic and predictive role of various T cell infiltrates, the role of the humoral immune response in this context has long been overlooked. This study aimed to investigate the clinicopathological correlates and prognostic impact of B cell and plasma cell infiltration in epithelial ovarian cancer (EOC).

METHODS

Immunohistochemical expression of immunoglobulin kappa C (IGKC), CD20 and CD138 was analysed in tissue microarrays with tumours from 154 incident cases of EOC from two pooled prospective population-based cohorts. Subsets of corresponding benign-appearing fallopian tubes (n = 38) and omental metastases (n = 33) were also analysed. Kaplan-Meier analysis and Cox regression analysis were used to determine the impact of immune-cell specific IGKC, CD20 and CD138 expression on overall survival and ovarian cancer-specific survival.

RESULTS

High IGKC expression correlated significantly with expression of CD20 (p = 0.001) and CD138 (p = 0.035). Expression of IGKC as well as CD138 was significantly higher in primary tumours than in fallopian tubes (p = 0.004 and p = 0.001, respectively). High CD20 and CD138 expression correlated significantly with high tumour grade (p = 0.032 and p = 0.030, respectively). CD20 and IGKC expression was not prognostic but univariable Cox regression analysis revealed high CD138 expression to correlate with a significantly reduced overall survival (HR = 2.20; 95 % CI 1.34-3.55; p-0.001) as well as ovarian cancer-specific survival (HR = 1.95; 95 % CI 1.28-2.98; p = 0.002). The prognostic impact was independent of established clinical parameters (age, grade, clinical stage) as shown in multivariable analysis (HR = 2.28; 95 % CI 1.39-3.75; p = 0.001).

CONCLUSIONS

In conclusion, our results demonstrate that plasma cell infiltration in epithelial ovarian cancer has a significant impact on tumour progression and prognosis. The important role of the humoral immune system merits further study and may be harnessed as immune modulatory strategies in cancer therapy.

Prognostic impact of tumor-associated B cells and plasma cells in colorectal cancer

587

Background: Multiple studies have described associations between infiltrating immune cells, prognosis and treatment response in cancer. However, the clinical relevance has most often been attributed to the T-cell linage, whereas the humoral immune response is less investigated. In colorectal cancer (CRC), accumulation of CD20-positive B lymphocytes at the advancing margin of metastatic CRC has been demonstrated to correlate with prolonged survival. This study aimed to further investigate the clinicopathological correlates and prognostic impact of B cell and plasma cell infiltration in colorectal cancer (CRC). Methods: Immunohistochemical expression of CD20 and CD138 in was analyzed in tissue microarrays with tumors from 557 incident cases of CRC from the Malmö Diet and Cancer Study, a prospective population-based cohort. Kaplan-Meier analysis and Cox regression analysis were used to determine the impact of CD20 and CD138 expression on 5-year overall survival (OS). Results: CD20 expression could be evaluated in 549 (98.6 %) cases and CD38 in 534 (95.9 %) cases. CD20 expression correlated significantly with both immune cell-specific and tumor-specific expression of CD138 (p < 0.001 and p = 0.001, respectively). Furthermore, immune cell-specific CD20 and CD138 expression as well as tumor-specific CD138 expression correlated significantly with lower T-stage (p < 0.001, p < 0.001 and p = 0.002, respectively). A higher density of CD20+ cells correlated significantly with an improved OS (HR = 0.66, 95 % CI 0.50-0.86), remaining significant in multivariable analysis adjusted for age, TNM stage, differentiation grade and vascular invasion (HR = 0.65; 95% CI 0.48-0.90). Neither immune cell nor tumor cell-specific CD138 expression was significantly associated with prognosis. Conclusions: Our results demonstrate that increased B cell infiltration in CRC is an independent factor of improved prognosis. Moreover, the study provides a first demonstration of the expression and clinicopathological correlates of immune cell-specific CD138 expression in CRC, thus providing a further characterization of the immune landscape in this type of cancer.

Expression and prognostic significance of the polymeric immunoglobulin receptor in epithelial ovarian cancer

BACKGROUND

High expression of the polymeric immunoglobulin receptor (PIGR) has previously been associated with a favourable prognosis in a few cancer forms, but its expression and relationship with clinical outcome in epithelial ovarian cancer (EOC) has not yet been reported. The aim of this study was therefore to examine the clinicopathological correlates and prognostic significance of PIGR expression in EOC.

METHODS

After an initial screening in the Human Protein Atlas portal, a validated antibody was selected for extended analysis of immunohistochemical PIGR expression in tissue microarrays with tumours from 154 incident cases of EOC from two pooled prospective population-based cohorts. Subsets of corresponding benign-appearing fallopian tubes (n = 38) and omental metastases (n = 33) were also analysed. Kaplan-Meier analysis and Cox regression analysis were applied to examine the impact of PIGR expression on overall survival (OS) and ovarian cancer-specific survival (OCSS).

RESULTS

PIGR expression was significantly higher in fallopian tubes compared to primary tumours and metastases (p < 0.001) and lower in carcinoma of the serous subtype compared to other carcinomas (p < 0.001). PIGR expression was significantly associated with lower grade (p = 0.001), mucinous histological subtype (p = 0.002), positive progesterone receptor expression (p = 0.009) and negative or low Ki-67 expression (p = 0.003). Kaplan-Meier analysis revealed a significantly improved OS (p = 0.013) and OCSS (p = 0.009) for patients with tumours displaying high expression of PIGR. These associations were confirmed in unadjusted Cox regression analysis (HR = 0.48; 95% CI 0.26-0.87; p = 0.015 for OS and HR = 0.43, 95% CI 0.22-0.82; p = 0.011 for OCSS) but did not remain significant after adjustment for age, grade and clinical stage.

CONCLUSIONS

This study provides a first demonstration of PIGR expression in human fallopian tubes, primary EOC tumours and metastases. High tumour-specific expression of PIGR was found to be associated with a favourable prognosis in unadjusted, but not in adjusted, analysis. These findings are novel and merit further investigation.