Major histocompatibility complex class I expression impacts on patient survival and type and density of immune cells in biliary tract cancer

Background:

Biliary tract cancers (BTC) are rare malignant tumours with a poor prognosis. Previously, we have presented a detailed characterisation of the inflammatory infiltrate in BTC. Here, we analysed the impact of the expression of major histocompatibility complex class I (MHC I) on patient survival and the quantity, as well as the quality of tumour-infiltrating immune cell types in BTC.

Methods:

MHC I expression was assessed semi-quantitatively in 334 BTC, including extrahepatic (n=129) and intrahepatic cholangiocarcinomas (n=146), as well as adenocarcinomas of the gallbladder (n=59). In addition, 71 high-grade biliary intraepithelial lesions (BilIN 3) were included. Results were correlated with data on antitumour inflammation and investigated with respect to their association with clinicopathological variables and patient survival.

Results:

BTC showed a wide spectrum of different MHC I expression patterns ranging from complete negativity in some tumours to strong homogenous expression in others. In BilIN 3, significantly higher MHC I expression levels were seen compared to invasive tumours (P=0.004). Patients with strong tumoural MHC I expression had a significantly higher overall survival probability (median survival benefit: 8 months; P=0.006). MHC I expression strongly correlated with the number of tumour-infiltrating T-lymphocytes (CD4⁺ and CD8⁺) and macrophages.

Conclusions:

Differences of MHC I expression predict patient outcome and show correlations with specific components of the inflammatory infiltrate in BTC. These findings contribute to a better understanding of immune response and immune escape phenomena in cholangiocarcinogenesis.     

The intratumoural subsite and relation of CD8+ and FOXP3+ T lymphocytes in colorectal cancer provide important prognostic clues

Background:

To find improved tools for prognostic evaluation in patients with colorectal cancer (CRC), we have analysed how infiltration of cytotoxic T lymphocytes (CD8⁺) and regulatory T lymphocytes (FoxP3⁺) correlates to prognosis, not only according to quantity and relation, but also to subsite within tumours of different molecular characteristics (microsatellite instability and CpG island methylator phenotype status).

Methods:

CD8 and FOXP3 expression was evaluated by immunohistochemistry in 426 archival tumour tissue samples from patients surgically resected for CRC. The average infiltration of CD8⁺ and FOXP3⁺ cells was assessed along the tumour invasive front, in the tumour centre and within the tumour epithelium (intraepithelial).

Results:

We found that infiltration of CD8⁺ T lymphocytes within the tumour epithelium provided the strongest prognostic information (P<0.001). At the tumour invasive front and tumour centre, FOXP3 expression withheld the strongest association to prognosis (P<0.001), suggesting FOXP3⁺ T-lymphocyte infiltration to be a better prognostic tool than CD8⁺ T lymphocytes at these intratumoural subsites. We further analysed the possible prognostic impact of the relation between these T-cell subsets, finding that a high intraepithelial CD8 expression was associated with a better patient outcome, independent of FOXP3 infiltration. In groups of low intraepithelial CD8 expression, however, a high infiltration rate of FOXP3⁺ cells at the tumour invasive front, significantly improved prognosis.

Conclusions:

Analyses of intraepithelial infiltration of CD8⁺ T lymphocytes, infiltration of FOXP3⁺ T lymphocytes at the tumour front or centre, and the relation between these subsets, may be a valuable tool for predicting prognosis in colon cancer.     

Tumour-infiltrating inflammation and prognosis in colorectal cancer: systematic review and meta-analysis

Background:

The role of tumour-infiltrating inflammation in the prognosis of patients with colorectal cancer (CRC) has not been fully evaluated. The primary objective of our meta-analysis was to determine the impact of tumour-infiltrating inflammation on survival outcomes.

Methods:

Ovid MEDLINE and EMBASE were searched to identify studies reporting the prognostic significance of tumour-infiltrating inflammation for patients with CRC. The primary outcome measures were overall survival (OS), cancer-specific survival (CS) and disease-free survival (DFS).

Results:

A total of 30 studies involving 2988 patients were identified. Studies were subdivided into those considering the associations between CRC survival and generalised tumour inflammatory infiltrate (n=12) and T lymphocyte subsets (n=18). Pooled analyses revealed that high generalised tumour inflammatory infiltrate was associated with good OS (HR, 0.59; 95% CI, 0.48–0.72), CS (HR, 0.40; 95% CI, 0.27–0.61) and DFS (HR, 0.72; 95% CI, 0.57–0.91). Stratification by location and T lymphocyte subset indicated that in the tumour centre, CD3⁺, CD8⁺ and FoxP3⁺ infiltrates were not statistically significant prognostic markers for OS or CS. In the tumour stroma, high CD8⁺, but not CD3⁺ or FoxP3⁺ cell infiltrates indicated increased OS. Furthermore, high CD3⁺ cell infiltrate was detected at the invasive tumour margin in patients with good OS and DFS; and high CCR7⁺ infiltrate was also indicated increased OS.

Conclusion:

Overall, high generalised tumour inflammatory infiltrate could be a good prognostic marker for CRC. However, significant heterogeneity and an insufficient number of studies underscore the need for further prospective studies on subsets of T lymphocytes to increase the robustness of the analyses.     

Low stromal Foxp3+ regulatory T-cell density is associated with complete response to neoadjuvant chemoradiotherapy in rectal cancer

Background:

Foxp3⁺ regulatory T cells (Tregs) play a vital role in preventing autoimmunity, but also suppress antitumour immune responses. Tumour infiltration by Tregs has strong prognostic significance in colorectal cancer, and accumulating evidence suggests that chemotherapy and radiotherapy efficacy has an immune-mediated component. Whether Tregs play an inhibitory role in chemoradiotherapy (CRT) response in rectal cancer remains unknown.

Methods:

Foxp3⁺, CD3⁺, CD4⁺, CD8⁺ and IL-17⁺ cell density in post-CRT surgical samples from 128 patients with rectal cancer was assessed by immunohistochemistry. The relationship between T-cell subset densities and clinical outcome (tumour regression and survival) was evaluated.

Results:

Stromal Foxp3⁺ cell density was strongly associated with tumour regression grade (P=0.0006). A low stromal Foxp3⁺ cell density was observed in 84% of patients who had a pathologic complete response (pCR) compared with 41% of patients who did not (OR: 7.56, P=0.0005; OR: 5.27, P=0.006 after adjustment for presurgery clinical factors). Low stromal Foxp3⁺ cell density was also associated with improved recurrence-free survival (HR: 0.46, P=0.03), although not independent of tumour regression grade.

Conclusions:

Regulatory T cells in the tumour microenvironment may inhibit response to neoadjuvant CRT and may represent a therapeutic target in rectal cancer.     

Automated prognostic pattern detection shows favourable diffuse pattern of FOXP3+ Tregs in follicular lymphoma

Background:

Histopathological prognostication relies on morphological pattern recognition, but as numbers of biomarkers increase, human prognostic pattern-recognition ability decreases. Follicular lymphoma (FL) has a variable outcome, partly determined by FOXP3 Tregs. We have developed an automated method, hypothesised interaction distribution (HID) analysis, to analyse spatial patterns of multiple biomarkers which we have applied to tumour-infiltrating lymphocytes in FL.

Methods:

A tissue microarray of 40 patient samples was used in triplex immunohistochemistry for FOXP3, CD3 and CD69, and multispectral imaging used to determine the numbers and locations of CD3⁺, FOXP3/CD3⁺ and CD69/CD3⁺ T cells. HID analysis was used to identify associations between cellular pattern and outcome.

Results:

Higher numbers of CD3⁺ (P=0.0001), FOXP3/CD3⁺ (P=0.0031) and CD69/CD3⁺ (P=0.0006) cells were favourable. Cross-validated HID analysis of cell pattern identified patient subgroups with statistically significantly different survival (35.5 vs 142 months, P=0.00255), a more diffuse pattern associated with favourable outcome and an aggregated pattern with unfavourable outcome.

Conclusions:

A diffuse pattern of FOXP3 and CD69 positivity was favourable, demonstrating ability of HID analysis to automatically identify prognostic cellular patterns. It is applicable to large numbers of biomarkers, representing an unsupervised, automated method for identification of undiscovered prognostic cellular patterns in cancer tissue samples.     

Immune cell infiltration as an indicator of the immune microenvironment of pancreatic cancer

Background:

The host immune reaction is represented by immune/inflammatory cell infiltrates. Here we systematically analysed tumour-infiltrating immune/inflammatory cells in pancreatic ductal carcinoma (PDC) and evaluated their clinicopathological impact.

Methods:

Using immunohistochemistry, we examined tumour-infiltrating CD68⁺ pan-macrophages, HLA-DR⁺CD68⁺ M1 macrophages (M1), CD163⁺ or CD204⁺ M2 macrophages (M2), CD66b⁺ neutrophils (Neu), CD4⁺ T cells (CD4⁺T), CD8⁺ T cells (CD8⁺T), and FOXP3⁺CD4⁺ regulatory T cells (Treg) in 212 cases of PDC, and conducted correlation and survival analyses using the Kaplan–Meier method and Cox proportional hazards model.

Results:

Higher levels of tumour-infiltrating pan-macrophages, M2, Neu, or the ratio of Tregs to CD4⁺T (%Treg) were significantly associated with shorter survival, whereas higher levels of tumour-infiltrating CD4⁺T, CD8⁺T, or the ratio of M1 to pan-macrophages (%M1) were significantly associated with longer survival. Survival analysis of pairs of these variables revealed that some of the resulting patient groups had exclusively longer survival. We then connected the apparently related factors, and two significant variables emerged: tumour-infiltrating CD4⁺T^high/CD8⁺T^high/%Treg^low and tumour-infiltrating %M1^high/M2^low. Multivariate survival analysis revealed that these variables were significantly correlated with longer survival and had a higher hazard ratio.

Conclusion:

Tumour-infiltrating CD4⁺T^high/CD8⁺T^high/%Treg^low and %M1^high/M2^low are independent prognosticators useful for evaluating the immune microenvironment of PDC.     

PD-1+ CD8+ T cells are exhausted in tumours and functional in draining lymph nodes of colorectal cancer patients

Background:

The blockade of PD-1–PD-L1 pathway is emerging as an effective therapeutic strategy for several advanced cancers. But the immune regulatory role of PD-1–PD-L1 pathway is not clear in colorectal cancer (CRC) patients. This study aims to evaluate the role of PD-1–PD-L1 pathway in CD8⁺ T-cell functions in tumour-draining lymph nodes (TDLNs) and tumours of CRC patients.

Methods:

PD-1 expression on CD8⁺ T cells was examined by flow cytometry, and PD-L1 expression in TDLNs and tumour tissues were examined by immunohistochemistry. Production of IFN-γ, IL-2 and expression of granzyme B, perforin in CD8⁺ T cells were detected by intracellular staining.

Results:

PD-1 expression is markedly upregulated on CD8⁺ T cells in TDLNs and tumours compared with that in peripheral blood. PD-1-expressing CD8⁺ T cells are competent for production of cytokine (IL-2 and IFN-γ) and perforin in the tumour-free lymph nodes (TFLNs), but exhibit exhausted phenotypes in tumours. In addition, PD-L1 is highly expressed in tumours rather than TFLNs, which is closely correlated with the impairment of IFN-γ production of tumour-infiltrating PD-1⁺ CD8⁺ T cells.

Conclusions:

Our findings suggest a suppressive effect of PD-1 on CD8⁺ T-cell function in tumours, but not in TFLNs.     

Tumour-associated CD66b+ neutrophil count is an independent prognostic factor for recurrence in localised cervical cancer

Background:

The prognostic impact of tumour-promoting immune cells in cervical cancer is unclear.

Methods:

Federation of Gynaecology and Obstetrics (FIGO) stage IB and IIA cervical cancer patients (N=101) were assessed for tumour-associated CD66b⁺ neutrophils and CD163⁺ macrophages by immunohistochemistry in whole tissue sections using stereology. Results were correlated with previous results on tumour-infiltrating CD3⁺, CD4⁺, and CD8⁺ lymphocytes in the same cohort with recurrence-free survival (RFS) as end point.

Results:

The highest densities of CD66b⁺ neutrophils and CD163⁺ macrophages were observed in the peritumoural compartment (median 53.1 cells mm⁻² and 1.3% area fraction, respectively). Above median peritumoural and stromal CD66b⁺ neutrophils and peritumoural CD163⁺ macrophages were significantly associated with short RFS. Multivariate analysis identified high peritumoural neutrophils (HR 2.27; 95% CI 1.09–4.75; P=0.03), low peritumoural CD8⁺ lymphocytes (HR 3.67; 95% CI 1.63–8.25; P=0.002), and lymph node metastases (HR 2.70; 95% CI 1.26–5.76; P=0.01) as independent prognostic factors for short RFS, whereas CD163⁺ macrophages were not significant. An index of combined intratumoral and peritumoral CD66b⁺ neutrophils to CD8⁺ lymphocytes had good discriminatory power for each quartile with 5-year RFS of 92%, 80%, 62%, and 44% (P=0.001).

Conclusion:

Tumour-associated neutrophil count is an independent prognostic factor for short RFS in localised cervical cancer. Combining CD66b and CD8 may further improve prognostic stratification. These findings require prospective validation.     

Stromal infiltration of CD8 T cells is associated with improved clinical outcome in HPV-positive oropharyngeal squamous carcinoma

Background:

Patients with human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma (OPSCC) have a better prognosis than those with HPV-negative tumours. There is interest in de-escalating their treatment but strategies are needed for risk stratification to identify subsets with a poor prognosis. This study investigated tumour-infiltrating lymphocytes (TILs) in relation to HPV tumour status and patient survival.

Methods:

Biopsies from 218 patients diagnosed with OPSCC between 2002 and 2011, who underwent chemo/radiotherapy were analysed for HPV by PCR, in-situ hybridisation and p16 immunohistochemistry (IHC). One hundred and thirty-nine samples with concordant HPV detection were analysed for CD3, CD4, CD8 and FoxP3 expression in tumour and stromal regions using multiplexIHC and multispectral image analysis. Labelling of smooth muscle actin (SMA) identified activated stroma.

Results:

Human papillomavirus-positive compared with HPV-negative OPSCC had higher infiltration in both tumour and stromal areas of CD4 and CD8 T cells but not FoxP3 T regulatory cells. Only CD3+CD8+ stromal and not tumour area infiltration was associated with increased survival (P=0.02). There was significantly higher SMA expression in HPV-positive compared with -negative tumours, which did not correlate with survival.

Conclusions:

Studies of TILs for risk stratification in OPSCC should assess stromal infiltration.     

Tumour-infiltrating CD8+ lymphocytes as an independent predictive factor for pathological complete response to primary systemic therapy in breast cancer

Background:

Tumour-infiltrating lymphocytes (TILs) are known to be associated with response to primary systemic therapy (PST) in breast cancer. This study was conducted to assess the association of TIL subsets with pathological complete response (pCR) after PST in breast cancer in relation to breast cancer subtype, breast cancer stem cell (BCSC) phenotype and epithelial–mesenchymal transition (EMT).

Methods:

The pre-chemotherapeutic biopsy specimens of 153 breast cancer patients who underwent surgical resection after anthracycline- or anthracycline/taxane-based PST were analysed. TIL subsets (CD4+, CD8+, and FOXP3+ TILs), BCSC phenotype, and the expression of EMT markers were evaluated by immunohistochemistry and were correlated with pCR after PST.

Results:

Infiltration of CD4+ and CD8+ T lymphocytes was closely correlated with BCSC phenotype and EMT. High levels of CD4+, CD8+, and FOXP3+ TILs were associated with pCR, and CD8+ TILs were found to be an independent predictive factor for pCR. In addition, CD8+ TILs were associated with pCR irrespective of breast cancer subtype, CD44+/CD24− phenotype, EMT, and chemotherapeutic regimen in subgroup analyses.

Conclusion:

These findings indicate that CD8+ cytotoxic T lymphocytes are a key component of TILs associated with chemo-response and can be used as a reliable predictor of response to anthracycline- or anthracycline/taxane-based PST in breast cancer.     

Tumour-infiltrating CD4+ and CD8+ lymphocytes as predictors of clinical outcome in glioma

Background:

T lymphocyte infiltration has been detected in glioma, although its significance remains unclear. The purpose of the present study was to explore the prognostic value of CD4⁺ and CD8⁺ tumour-infiltrating lymphocytes (TILs) in glioma, and the prognostic value of infiltrating Forkhead box protein 3 (FoxP3⁺) regulatory T cells were also investigated.

Methods:

CD4⁺, FoxP3⁺ and CD8⁺ TILs were assessed by immunohistochemical staining of tissue microarray cores from 284 gliomas. Kaplan–Meier analysis and Cox proportional hazards models were used to examine the survival function of these TILs in 90 glioblastoma patients.

Results:

The number of CD8⁺ TILs was inversely correlated with tumour grade (P=0.025), whereas the number of CD4⁺ TILs was positively correlated with tumour grade (P=0.002). FoxP3⁺ TILs were only observed in glioblastomas, but not in low-grade astrocytomas or oligodendroglial tumours. Among patients with glioblastoma, none of CD4⁺ TILs, FoxP3⁺ TILs and CD8⁺ TILs alone was significantly associated with patient prognosis. However, the presence of high CD4⁺ and low CD8⁺ TIL levels was an independent predictor of poor progress-free survival (multivariate hazard ratio (HR) 1.618, 95% confidence interval (CI) 1.245–2.101, P<0.001) and poor overall survival (multivariate HR 1.508, 95% CI 1.162–1.956, P=0.002). Moreover, pseudoprogression was more often found in patients with high CD4⁺ TILs and high CD8⁺ TILs.

Conclusions:

The combination of CD4⁺ and CD8⁺ TILs is a predictor of clinical outcome in glioblastoma patients, and a high level of CD4⁺ TILs combined with low CD8⁺ TILs was associated with unfavourable prognosis.     

Intraepithelial CD8-positive T lymphocytes predict survival for patients with serous stage III ovarian carcinomas: relevance of clonal selection of T lymphocytes

Background:

The aim of this study was to investigate the prognostic effect of tumour-infiltrating lymphocytes (TILs) in serous stage III ovarian carcinoma to determine TIL clonality and to correlate this to Her2/neu expression.

Methods:

Formalin-fixed and paraffin-embedded ovarian carcinomas were examined for CD20-, CD3-, CD4- and CD8-positive lymphocytes (n=100), and for Her2/neu-positive tumour cells (n=55/100) by immunohistochemistry. Clonality analysis was carried out by T-cell receptor γ (TCRγ) gene rearrangements (n=93/100). Statistical analyses included experimental and clinico-pathological variables, as well as disease-free (DFS) and overall (OS) survival.

Results:

CD20-positive B lymphocytes were present in 57.7% (stromal)/33.0% (intraepithelial) and CD3-positive T lymphocytes in 99.0% (stromal)/90.2% (intraepithelial) of ovarian carcinomas. Intraepithelial CD3-positive T lymphocytes were correlated with improved DFS in optimally debulked patients (P=0.0402). Intraepithelial CD8-positive T lymphocytes were correlated with improved OS in all optimally debulked patients (P=0.0201) and in those undergoing paclitaxel/carboplatin therapy (P=0.0092). Finally, rarified and clonal TCRγ gene rearrangements were detected in 37 out of 93 (39.8%) and 15 out of 93 (16.1%) cases, respectively. This was marginally associated with improved DFS (P=0.0873). Despite a significant correlation of HER2/neu status and intraepithelial CD8-positive lymphocytes (P=0.0264), this was non-directional (R=−0.257; P=0.0626).

Conclusion:

Improved survival of ovarian cancer patients is related to the infiltration, clonal selection and intraepithelial persistence of T lymphocytes.     

Prognostic and predictive value of immunological parameters for chemoradioimmunotherapy in patients with pancreatic adenocarcinoma

Background:

Chemoradioimmunotherapy of patients with pancreatic adenocarcinoma from the CapRI trial did not show any benefit of interferon-α in addition to a 5-fluorouracil (5FU)-based treatment. The aim of this study was to identify immunological parameters in patients from this trial to be used for predictive and/or prognostic purposes.

Methods:

The following methods were used: tumour immunohistology, FACS analyses, cytokine measurement, as well as cytotoxicity and ELIspot. Immunological parameters were correlated with patients'' survival using the Kaplan–Meier method.

Results:

Irrespective of therapy type, high lymphocyte accumulation in tumours and frequencies of NK cells and effector (eff) CD8⁺ T cells in peripheral blood of the patients were associated with patients'' survival. Amount of CD3⁺ and effector-memory CD8⁺ blood lymphocytes, expression of CD152 and interleukin (IL)-2 serum level showed a predictive value for chemoradioimmunotherapy. Tumoural accumulation of CD3⁺ and CD8⁺ cells was predictive for outcome of chemotherapy alone. Besides, we identified the frequencies of CD3⁺ lymphocytes, effCD8⁺ T cells and NK cells in the peripheral blood of the patients, and IL-10 amount in serum, to be predictive values for 5FU-based chemotherapy.

Conclusions:

Immunological parameters, identified in this trial as possible markers, may be of interest in personalized medicine towards the improvement of the treatment and prognosis of pancreatic carcinoma patients.     

Intratumoral regulatory T cells upregulate immunosuppressive molecules in head and neck cancer patients

Background:

Although regulatory T cells (Treg) are highly enriched in human tumours compared with peripheral blood, expression of the immune-checkpoint receptors, immunosuppressive molecules and function of Treg in these two sites remains undefined.

Methods:

Tumour-infiltrating lymphocytes and peripheral blood lymphocytes were isolated from a cohort of head and neck squamous cell carcinoma (HNSCC) patients. The immunosuppressive phenotypes and function of intratumoral Treg were compared with those of peripheral blood Treg.

Results:

The frequency of immune-checkpoint receptor-positive cells was higher on intratumoral FOXP3⁺CD25^hi Treg compared with circulating Treg (CTLA-4, P=0.002; TIM-3, P=0.002 and PD-1, P=0.002). Immunosuppressive effector molecules, LAP and ectonucleotidase CD39 were also upregulated on intratumoral FOXP3⁺ Treg (P=0.002 and P=0.004, respectively). CTLA-4 and CD39 were co-expressed on the majority of intratumoral FOXP3⁺CD4⁺ Treg, suggesting that these molecules have a key role in regulatory functions of these cells in situ. Notably, intratumoral Treg exhibited more potently immunosuppressive activity than circulating Treg.

Conclusion:

These results indicate that intratumoral Treg are more immunosuppressive than circulating Treg and CTLA-4 and CD39 expressed can be potential target molecules to inhibit suppressive activities of intratumoral Treg in situ.     

Tumour-infiltrating CD68+ and CD57+ cells predict patient outcome in stage II–III colorectal cancer

Background:

The aim of our study was to evaluate the prognostic role of immunological microenvironnement in stage II–III CRC patients.

Methods:

We constructed a tissue microarray from 196 consecutive patients with stage II–III CRC and compared CD3, CD4, CD8, CD57, CD68, CXCL9/MIG, CXCL13, and PPARγ immunoreactivity in tumour samples and their matched non-tumour tissue. We assessed their association with relapse-free survival (RFS; primary endpoint) and overall survival (OS) in multivariate Cox models.

Results:

Low densities of CD57+ and CD68+ tumour-infiltrating cells (TIC) independently predicted worse outcomes. A prognostic score combining CD57 (+, > vs −, ⩽2 cells per spot) and CD68 (+, >0 vs −, =0 cells per spot) TIC density discriminated CRC patients at low (CD68+/CD57+), intermediate (CD68+/CD57−), or high (CD68−/CD57−) risk, with hazard ratios for the intermediate-risk and high-risk groups of 2.7 (95% confidence interval (CI): 1.3–5.8) and 9.0 (3.2–25.4) for RFS, and 2.5 (1.2–5.1) and 10.6 (3.8–29.2) for OS, respectively, as compared with the low-risk group. Corresponding 5-year survival rates (95% CI) in the low-, moderate- and high-risk groups were 84% (71–91), 65% (54–74), and 12% (2–47), respectively, for RFS, and 91% (80–96), 76% (66–84), and 25% (7–59), respectively, for OS.

Conclusion:

Tumour CD57+ and CD68+ TIC density assessment independently predicts survival in patients with stage II–III CRC. If validated, our score based on a quick, inexpensive, and well-established method such as point counting on diagnostic tissue sections could be used routinely as a prognostic tool in CRC patients.     

IFN-γ from lymphocytes induces PD-L1 expression and promotes progression of ovarian cancer

Background:

PD-L1 (programmed cell death 1 ligand 1) on tumour cells suppresses host immunity through binding to its receptor PD-1 on lymphocytes, and promotes peritoneal dissemination in mouse models of ovarian cancer. However, how PD-L1 expression is regulated in ovarian cancer microenvironment remains unclear.

Methods:

The number of CD8-positive lymphocytes and PD-L1 expression in tumour cells was assessed in ovarian cancer clinical samples. PD-L1 expression and tumour progression in mouse models under conditions of altering IFN-γ signals was assessed.

Results:

The number of CD8-positive cells in cancer stroma was very high in peritoneally disseminated tumours, and was strongly correlated to PD-L1 expression on the tumour cells (P<0.001). In mouse models, depleting IFNGR1 (interferon-γ receptor 1) resulted in lower level of PD-L1 expression in tumour cells, increased the number of tumour-infiltrating CD8-positive lymphocytes, inhibition of peritoneal disseminated tumour growth and longer survival (P=0.02). The injection of IFN-γ into subcutaneous tumours induced PD-L1 expression and promoted tumour growth, and PD-L1 depletion completely abrogated tumour growth caused by IFN-γ injection (P=0.01).

Conclusions:

Interferon-γ secreted by CD8-positive lymphocytes upregulates PD-L1 on ovarian cancer cells and promotes tumour growth. The lymphocyte infiltration and the IFN-γ status may be the key to effective anti-PD-1 or anti-PD-L1 therapy in ovarian cancer.     

Microsatellite instable vs stable colon carcinomas: analysis of tumour heterogeneity,inflammation and angiogenesis

Background:

Microsatellite instability (MSI) accounts for 15% of all colorectal tumours. Several specific clinicopathologicals (e.g., preference for the proximal colon over the distal colon, improved prognosis and altered response to chemotherapeutics) are described for this subset of tumours. This study aimed to analyse morphological, inflammatory and angiogenic features of MSI vs microsatellite stable (MSS) tumours.

Methods:

Twenty-seven MSS and 29 MSI, TNM stage matched, colorectal tumours were selected from the archive of the Department of Pathology, UZ Leuven. Morphology was analysed on haematoxylin–eosin sections. Immunohistochemistry for CD3, CD4, CD8, CD20 and CD68 was used to map tumour infiltration in both a digital and traditional microscope-based manner for all distinct morphological components of the tumour. CD31 immunostains were performed to assess angiogenesis.

Results:

Morphological tumour heterogeneity was a marked feature of MSI tumours, occurring in 53% of the cases as compared with 11% of the MSS tumours (P<0.001). Digital immune quantification showed an increased number of tumour-infiltrating cytotoxic T-lymphocytes (CD8+) in MSI compared with MSS tumours for both the tumour (P=0.02) and peritumoural area (P=0.03). Traditional microscope-based quantification confirmed these results (P<0.001 for both) and, in addition, revealed large numbers of CD68+ macrophages in the peritumoural area of MSI cancers (P=0.001). Moreover, traditional microscope-based analysis was able to distinguish between lymphocytes directly infiltrating the tumoural glands (intra-epithelial) and those infiltrating only the neoplastic stroma around the glands (intratumoural). Quantification showed high numbers of intra-epithelial CD3+, CD4+, CD8+, CD20+ and CD68+ cells in MSI compared with MSS cancers (P<0.001, P=0.01, P<0.001, P<0.001 and P=0.006, respectively). Higher microvessel density (MVD) was observed in MSI tumours compared with their MSS counterpart.

Conclusions:

Mixed morphology, reflecting tumour heterogeneity, is an important feature of MSI tumours and may have both diagnostic and therapeutic impact. The inflammatory reaction also presented with significant differences in MSI vs MSS colorectal tumours. MSI cancers showed mainly infiltration by cytotoxic T-cells in both the tumour and the close border around the tumour, as well as increased intra-epithelial infiltration in contrast to MSS tumours. The type of immune cell and the compartment it resides in (intratumoural or intra-epithelial) depend both on MSI status and morphology. Finally, MSI tumours showed a higher angiogenic capacity represented by an increased MVD, hinting for possible therapeutic consequences.     

Mesenchymal stem cells are enriched in head neck squamous cell carcinoma,correlates with tumour size and inhibit T-cell proliferation

Background:

Cancer is a multifactorial disease not only restricted to transformed epithelium, but also involving cells of the immune system and cells of mesenchymal origin, particularly mesenchymal stem cells (MSCs). Mesenchymal stem cells contribute to blood- and lymph- neoangiogenesis, generate myofibroblasts, with pro-invasive activity and may suppress anti-tumour immunity.

Methods:

In this paper, we evaluated the presence and features of MSCs isolated from human head neck squamous cell carcinoma (HNSCC).

Results:

Fresh specimens of HNSCC showed higher proportions of CD90+ cells compared with normal tissue; these cells co-expressed CD29, CD105, and CD73, but not CD31, CD45, CD133, and human epithelial antigen similarly to bone marrow-derived MSCs (BM-MSCs). Adherent stromal cells isolated from tumour shared also differentiation potential with BM-MSCs, thus we named them as tumour-MSCs. Interestingly, tumour-MSCs showed a clear immunosuppressive activity on in vitro stimulated T lymphocytes, mainly mediated by indoelamine 2,3 dioxygenase activity, like BM-MSCs. To evaluate their possible role in tumour growth in vivo, we correlated tumour-MSC proportions with neoplasm size. Tumour-MSCs frequency directly correlated with tumour volume and inversely with the frequency of tumour-infiltrating leukocytes.

Conclusions:

These data support the concept that tumour-MSCs may favour tumour growth not only through their effect on stromal development, but also by inhibiting the anti-tumour immune response.