Upfront progression under pembrolizumab followed by a complete response after encorafenib and cetuximab treatment in BRAF V600E-mutated and microsatellite unstable metastatic colorectal cancer patient: A case report.

Two new treatments have recently become standard care for patients with metastatic colorectal cancer (mCRC): encorafenib (BRAF inhibitor) associated with cetuximab (anti-EGFR) in the second or third line of chemotherapy for BRAF V600E tumors, and pembrolizumab (an anti PD-1 immune checkpoint inhibitor) for tumors harboring microsatellite instability (MSI)-high and/or deficient mismatch repair (dMMR). Furthermore, 30% of BRAF V600E mutated mCRC are MSI/dMMR through a sporadic hypermethylation of the promoter of hMLH1. We report here, for the first time, the case of a patient with BRAF V600E, PIK3CA, and SMAD4 mutated and dMMR/MSI mCRC, in whom we observed an atypical response pattern under the sequence of pembrolizumab followed by the doublet encorafenib and cetuximab treatment. The patient was progressive after a single cycle of pembrolizumab followed by a rapid complete response after only 2 months of treatment with encorafenib and cetuximab, discovered during R0 cytoreduction surgery for peritoneal carcinomatosis.

MET alterations in biphasic squamoid alveolar papillary renal cell carcinomas and clinicopathological features.

Biphasic squamoid alveolar papillary renal cell carcinoma (BSA-PRCC) is a recently studied lesion considered a morphologic variant of papillary renal cell carcinoma (RCC), more closely related to type 1. Considering the role of proto-oncogene MET in both sporadic type 1 papillary RCC and hereditary papillary RCC, we aimed to explore the role of MET activation in the oncogenesis of BSA-PRCC. We identified 17 patients with either unique (n = 14) or multiple (n = 3) BSA-PRCC, all localized, and performed an integrative analysis of MET status in 18 formalin-fixed paraffin-embedded tumors combining next-generation sequencing analysis, fluorescent in situ hybridization and immunohistochemistry. Trisomy 7 was found in 86% of tumors (14/16) without MET amplification at 7q31 (15/15). A pathogenic MET genetic variant was identified in 60% (9/15) of cases, at the germline level in 57% (4/7) of tested patients or at the somatic level (5/11). MET expression was observed in all tumors with a higher value of combined score in large cells (mean 97%, range 80-100%) than in small cells (mean 74%, range 10-100%) and was lower in two cases without MET copy number gain. In conclusion, our study provides additional evidence to consider biphasic squamoid alveolar papillary RCC as a morphological variant of type 1 papillary renal RCC. Our data strongly suggest that MET represents a major oncogenic driver gene in BSA-PRCC, harboring a higher frequency of MET mutation that encourages to further explore the benefice of anti-MET targeted therapies for aggressive BSA-PRCC.

[Tumour deposition (TD), a probably underestimated poor prognostic criterion, to be taken into account in the therapeutic management of patients with stage III colon cancer]. / Les dépôts tumoraux (DT), un critère pronostique péjoratif probablement sous-estimé, à prendre en compte dans la prise en charge thérapeutique des malades atteints de cancer colique de stade III.

The management of colorectal cancer (CRC) relies heavily on TNM staging. In order to improve this staging, it is essential to identify all histological markers bearing a significant prognostic value. Among these, tumor deposits (TDs), defined as tumor foci in the pericolonic or perirectal adipose tissue with no residual lymph node tissue, have been shown to be associated with poor prognosis in cohort studies leading to their individualization in the TNM7 classification as pN1c. However, TDs are only considered in the absence of lymph node metastases. There is no consensus on this particular way of integrating TDs in the TNM classification. Indeed, at the time when the choice of the type of adjuvant treatment and its duration in stage III colon cancers (i.e. with lymph node metastases) is based on pT and pN criteria, taking into account TDs only in the absence of concomitant lymph node metastases is potentially responsible for a misclassification of some patients and wrong therapeutic decisions. In addition, many questions concerning the true definition of TDs, their origin, their prognostic value and the optimization of their consideration remain open. The objective of this review is to provide a synthesis of current knowledge on TDs in CRC, in view of their prognostic importance, their biological complexity and the scientific interest they are currently the subject of.

[Pathologist contribution in the diagnosis of hereditary predisposition to paranganglioma and pheochromocytoma]. / Apport du pathologiste dans les prédispositions héréditaires aux paragangliomes et phéochromocytomes.

Hereditary predispositions are responsible for more than 30% of or paraganglioma. Their identification is essential to optimize medical care and to offer an appropriate screening to relatives. To date, there are more than 15 known paraganglioma/pheochromocytoma predisposing genes. The most frequently involved are those encoding the succinate dehydrogenase (SDHx), accounting for half of cases and the VHL gene, causing the Von Hippel Lindau syndrome and representing approximately 20% of genetically determined cases. Patients with SDHB genes mutations have a higher risk of metastatic disease. An oncogenetic counseling is recommended to all patients developing one or several paragangliomas, isolated or associated with other tumors. Apart from the clinical presentation and in particular the syndromic forms characterized by specific tumor spectra, there is no validated morphological criterion allowing to suspect a hereditary form. On the other hand, pathologists have now access to several immunohistochemical tools allowing the identification of some hereditary forms, in particular those linked to the SDHx, VHL and FH genes. Thus, the loss of expression in immunohistochemistry of the SDHB or FH proteins orientates respectively, towards SDHx and FH genes, while the membrane expression of carbonic anhydrase IX (CA-IX) is a sensitive and specific tool pointing towards a VHL anomaly. Other immunohistochemical markers are under evaluation. A systematic SDHB immunohistochemical staining is recommended on all paragangliomas/pheochromocytomas in order to allow an early detection of the most common hereditary forms and to contribute to the interpretation of the genetic results in these patients seen in oncogenetics consultation.

[Study of the Human Papillomavirus (HPV) prevalence in head and neck carcinomas in a French monocentric cohort of 372 patients]. / Étude de la prévalence du papillomavirus (HPV) dans les cancers des voies aéro-digestives sur une cohorte unicentrique française de 372 patients.

INTRODUCTION: French data about HPV role in head and neck carcinomas are sparse, although French patients are mostly heavy smokers. In this series of oropharyngeal et non-oropharyngeal tumors, we aimed to determine what were the clinicopathological features associated with HPV and evaluate survival of patients according to HPV status. METHODS: Three hundred and seventy-two cases of head and neck squamous cell carcinomas were reviewed and clinicopathological data were detailed. For each case, we performed a HPV PCR and an immunostaining against p16 protein (paraffin embedded tissues). RESULTS: The series contained 90% of heavy smokers and 36% of tumors were located in oropharynx. HPV DNA was detected in 46% of oropharyngeal carcinomas and 16% of non-oropharyngeal carcinomas. Genotype 16 was the most frequently detected (84%). Clinicopathological features significantly associated with HPV DNA were: oropharyngeal location; absence of tobacco smoking; nodal involvement; poorly-differentiated non-keratinizing histology; positive p16 immunostaining. HPV infection was significantly associated with a longer survival for oropharyngeal carcinomas. It was not the case for non-oropharyngeal carcinomas. CONCLUSION: In this French series with lot of heavy smokers, under half of carcinomas are HPV induced. Clinicopathological features and survival data associated with HPV infection are the same as those classically described in literature.

Low risk of invasive lobular carcinoma of the breast in carriers of BRCA1 (hereditary breast and ovarian cancer) and TP53 (Li-Fraumeni syndrome) germline mutations.

BACKGROUND: Invasive lobular carcinoma (ILC) of the breast has epidemiological, molecular and clinical specificities, and should likely be considered a unique entity. As for genetic susceptibility, CDH1 germline mutations predispose exclusively to ILC. Data are however scarce regarding ILC in women with BRCA1/2 (Hereditary Breast and Ovarian Cancer) and TP53 (Li-Fraumeni syndrome) germline mutations. METHODS: We included all breast cancers from female patients tested at our institute between 1992 and 2016 (n = 3469) for which pathology data were available. ILC proportion comparison according to mutational status was performed by a chi-squared test. The impact of susceptibility genes on ILC proportion was investigated by univariate logistic regression with wild-type patients as reference. RESULTS AND DISCUSSION: There were 265 (7.64%) ILC: 2/342 (0.58%) in BRCA1 patients, 24/238 (10%) in BRCA2 patients, 1/57 (1.75%) in TP53 patients and 238/2832 (8.4%) in non-carriers. The majority of breast cancers in all groups were invasive ductal and ductal in situ carcinomas. The difference in ILC proportion was highly significant (P < 0.001). Compared to wild-type patients, BRCA1 was associated with a lower ILC proportion (OR 0.064 [95% CI 0.016;0.259], P < 0.0001). BRCA2 OR was 1.222 [95%CI 0.785;1.902] (P = 0.374), TP53 OR was 0.195 [95%CI 0.027;1.412] (P = 0.105). ILC are therefore underrepresented in BRCA1 and TP53 mutation carriers. Formal significance (P = 0.05) was not reached for TP53, but statistical power was only 38%. Based on ILC incidence in the general population, we make the hypothesis that BRCA1 and TP53 do not predispose to ILC, as the few occurrences of ILC in mutation carriers could be attributed to chance and not to germline mutations. Our observations will be useful to clinical cancer geneticists managing patients with ILC, as a BRCA1 or TP53 mutation in these patients would be unlikely. Genetic counseling should be adapted accordingly.

[Immune-checkpoint and hemopathies]. / Les immune-checkpoints dans les hémopathies.

Immune-checkpoint inhibitors represent potent new therapies for most lymphomas, particularly for refractory diseases. Contrasting with solid tumors the majority of lymphoma are sensitive to conventional therapies and immunotherapies such as anti-CD20 or anti-CD30. But relapsing lymphoma or refractory disease have a very poor prognosis and new drugs are mandatory. Immune-checkpoint inhibitors targeting CTLA4, PD-1 et PD-L1 demonstrated efficiency with prolonged survivals even after bone marrow allograft for aggressive disease. Lymphomas differ from solid tumors as tumor cells belong to the immune compartment and therefore molecules targeting immune cells may act on both immune environment and tumor cells. Furthermore, PD-L1 expression in most lymphomas is related to tumor cell molecular alterations such as PD-L1 gene amplification or mutation. PD-L1 protein expression on tumor cells and immune cells, particularly it frequency and distribution vary according to different lymphoma subtype and it may help to assess diagnosis as it may predict therapeutical response.

[Current events in immunotherapy for upper aerodigestive tract cancer]. / Actualités sur l'immunothérapie en pathologie des voies aérodigestives supérieures.

Head and neck (HN) carcinomas (mostly represented by squamous cell carcinomas [SCC]) still have a poor prognosis, which could be dramatically improved with immunotherapy. Tumor's microenvironment changes, caused by many endogenous or exogenous events, can correlate with prognosis and therapeutic response. Here, we review recent data regarding HNSCC, nasopharyngeal carcinomas (NPC) and salivary gland malignant tumors, all three being potential target of immunotherapies. About half of HNSCC exhibit PD-L1 expression, this expression being upregulated in HPV-positive tumors. In recent clinical trials, a better therapeutic response to anti-PD-1 has been obtained in patients with higher PD-L1 expression. Food and Drug Administration (FDA) approved the use of these therapeutics without the screening of patients regarding PD-L1 status. Activation status, density and localisation of TIL as well as PD-L2, γ-interferon, inflammatory cytokines, epithelial-mesenchymal transition phenotype and mutational burden may all be potential therapeutic response markers. In Epstein-Barr Virus (EBV)-induced nasopharyngeal non-keratinizing cancer, PD-L1 is over-expressed compared to EBV negative-tumors. A 22 % response rate has been observed under anti-PD-1 treatment, among PD-L1-positive HNSCC patients. There is little data regarding microenvironment of salivary gland cancer. PD-L1 shows great heterogeneity in localisation, when expressed. A 11 % response rate has been obtained under anti-PD-1 treatment among PD-L1-positive NPC patients. A better understanding of immune checkpoint regulation processes needs to be achieved to allow patients with HN carcinomas to benefit from these promising immunotherapies.

Prevalence and clinical significance of nodular regenerative hyperplasia in liver biopsies.

BACKGROUND: Nodular regenerative hyperplasia (NRH) is a rare histological disorder associated with a wide variety of systemic diseases. AIMS: We aimed (i) to report the prevalence of NRH in a database of liver biopsies (LBs) and the frequency of portal hypertension (PHT) at diagnosis, and (ii) to investigate whether associated diseases and/or specific histological lesions, including abnormalities of the microvasculature, were related to PHT. METHODS: Patients with a histological diagnosis of NRH, referred by seven clinical departments, were retrospectively selected. Clinical, biological, radiological, haemodynamic and endoscopic data at diagnosis were recorded. LBs were reassessed for microvascular abnormalities. RESULTS: NRH was diagnosed in 4.4% of LBs (n = 159, male: 52%, mean age: 54). Among patients referred for unexplained liver enzyme abnormalities, 15% had NRH. PHT was present at diagnosis in 45 patients (38%), including 13 with portal thrombosis; 65% of patients had an associated disorder. Obliteration of portal vein branches, observed in the LBs of 17 patients (11%), was significantly associated with PHT (P = 0.02). Periportal angiomatosis, observed in 101 patients (63%), was associated with the absence of PHT (P < 10(-4) ). CONCLUSION: We suggest that NRH is a frequent histological lesion in the setting of unexplained liver enzyme abnormalities. PHT is present at the time of diagnosis in 1/3 of patients regardless of the presence of associated disease. The frequency of periportal angiomatosis in NRH without obliteration of portal vein branches, and its association with the absence of PHT suggest that obstructive portal venopathy would not represent the most frequent mechanism involved in NRH.

New developments and standard of care in the management of advanced gastric cancer.

Advanced gastric adenocarcinoma is a common disease with a poor prognosis whose treatment has for decades been based on cytotoxic chemotherapy, including platinum salts in first-line, and taxane or irinotecan in second or later line. Recent years have seen the emergence of new drugs that have improved patient survival, such as trastuzumab in first-line for HER2-positive tumors, ramucirumab alone or in combination with paclitaxel in second-line, and trifluridine-tipiracil beyond the second-line treatment. More recently, two monoclonal antibodies have demonstrated their efficacy in combination with oxaliplatin-based first-line chemotherapy, nivolumab (anti-PD1) for PD-L1 CPS ≥5 tumors, and zolbetuximab for tumors overexpressing Claudin 18.2. In addition, regorafenib has been also showed effective in phase 3 trial for heavily pretreated patients. Based on phase 2 studies, trastuzumab-deruxtecan was approved in 2022 by the EMA for HER2-positive pretreated patients. This agent is currently evaluated in phase 3 study (DESTINY-Gastric04 trial), as are several other anti-HER2 (zanidatamab, margetuximab, tucatinib), immune checkpoint inhibitors, or targeted therapies (anti-FGFR2b).

Chemotherapy-induced ileitis associated or not with colitis in digestive oncology patients: An AGEO multicentre study.

BACKGROUND: The characteristics and management of ileitis induced by chemotherapy in cancer patients are poorly described in the literature. METHODS: This retrospective multicentre study enroled patients hospitalized in a digestive oncology unit for a symptomatic chemotherapy-induced ileitis. RESULTS: Forty-three patients were included, with a regimen based on fluoropyrimidine and/or irinotecan in 95% of cases. Five patients were excluded due to the diagnosis of infectious ileitis (Clostridium difficile in 3 patients, Campylobacter jejuni in 1 patient and cytomegalovirus in 1 patient). The most frequently described symptoms were diarrhoea (77% including 54% of grade 3-4 diarrhoea), abdominal pain (58%), fever (51%) and vomiting (56%). An ileo-colonoscopy was performed in 35% of patients and did not show any specific results or severity criteria. The ileitis was complicated by bowel perforation and/or obstruction in 3 patients. Disease progression was favourable in 1-2 weeks in the vast majority of cases, on symptomatic treatment, allowing resumption of the chemotherapy regimen involved in 67% of patients. CONCLUSION: Chemotherapy-induced ileitis is a rare complication that most often involves fluoropyri-midine- and/or irinotecan-based regimens. In most cases, endoscopic examinations were not contributory and do not seem useful in the event of non-severe symptomatology which most often develops favourably on symptomatic therapy, allowing resumption of the chemotherapy involved.

MSI colorectal cancer, all you need to know.

Colorectal cancer management has been dramatically impacted by molecular profiling these last years. Among these molecular subgroups, patients with microsatellite instability (MSI) are of particular interest, owing to the prognostic and predictive value of this tumor biomarker. This review article explains the molecular abnormalities underlying MSI phenotype and the consequences of such molecular abnormalities on carcinogenesis, genetic instability and immune infiltration. It details the diagnostic methods for identifying MSI colorectal cancer patients and describes how the prognostic and theranostic values of this marker are impacting treatment decision-making for these patients in 2022.

Comparison of cold biopsy forceps vs cold snare for diminutive colorectal polyp removal: A multicenter non-inferiority randomized controlled trial.

BACKGROUND: European guidelines recommends the use of cold snare polypectomy (CSP) for removal of diminutive colorectal polyps (DCP). However, for DCP < 4 mm cold biopsy forceps (CBF) may be optional. We aimed to compare the efficacy of CSP with CBF for removal of DCP in routine colonoscopy. METHODS: We conducted a multicenter non-inferiority randomized controlled trial. After screening, 123 patients were prospectively included and 180 DCPs were removed by either CBF or CSP after randomization (1:1). The primary end-point was the histological complete resection rate defined by negative additional biopsies taken from the edge of the polypectomy ulcer site. RESULTS: Among DCPs, 121 (67.2%) adenomas or sessile serrated lesions were considered for the analysis. Polyps were 4 [1-5] mm in size, mostly flat (55.4%) and located in the proximal colon (44.6%). The en bloc resection rate was higher in the CSP group than the CBF group (91.7% vs. 42.6%, p < 0.001). The histological complete resection rate was comparable in the two groups (93.33% vs 90.16%; p = 0.527), even for polyps < 4 mm (91.30% vs 91.30%; p = 1). All specimens were retrieved and there was no difference in terms of procedure times and adverse events. Finally, univariate analysis did not identify any potential factor associated with complete resection rate. CONCLUSION: In this study, CSP was comparable to CBF for the removal of DCP. Therefore, CBF may be considered as an alternative technique for resection of DCP, together with CSP, ClinicalTrials.gov registry (NCT04727918).

Circumferential esophageal replacement by a decellularized esophageal matrix in a porcine model.

BACKGROUND: Tissue engineering is an attractive alternative to conventional esophageal replacement techniques using intra-abdominal organs which are associated with a substantial morbidity. The objective was to evaluate the feasibility of esophageal replacement by an allogenic decellularized esophagus in a porcine model. Secondary objectives were to evaluate the benefit of decellularized esophagus recellularization with autologous bone marrow mesenchymal stromal cells and omental maturation of the decellularized esophagus. METHODS: Eighteen pigs divided into 4 experimental groups according to mesenchymal stromal cells recellularization and omental maturation underwent a 5-cm long circumferential replacement of the thoracic esophagus. Turbo green florescent protein labelling was used for in vivo mesenchymal stromal cells tracking. The graft area was covered by a stent for 3 months. Clinical and histologic outcomes were analyzed over a 6-month period. RESULTS: The median follow-up was 112 days [5; 205]. Two animals died during the first postoperative month, 2 experienced an anastomotic leakage, 13 experienced a graft area stenosis following stent migration of which 3 were sacrificed as initially planned after successful endoscopic treatment. The stent could be removed in 2 animals: the graft area showed a continuous mucosa without stenosis. After 3 months, the graft area showed a tissue specific regeneration with a mature epithelium and muscular cells. Clinical and histologic results were similar across experimental groups. CONCLUSION: Circumferential esophageal replacement by a decellularized esophagus was feasible and allowed tissue remodeling toward an esophageal phenotype. We could not demonstrate any benefit provided by the omental maturation of the decellularized esophagus nor its recellularization with mesenchymal stromal cells.

Plasma CD27, a Surrogate of the Intratumoral CD27-CD70 Interaction, Correlates with Immunotherapy Resistance in Renal Cell Carcinoma.

PURPOSE: CD70 is a costimulatory molecule known to activate CD27-expressing T cells. CD27-CD70 interaction leads to the release of soluble CD27 (sCD27). Clear-cell renal cell carcinoma (ccRCC) expresses the highest levels of CD70 among all solid tumors; however, the clinical consequences of CD70 expression remain unclear. EXPERIMENTAL DESIGN: Tumor tissue from 25 patients with ccRCC was assessed for the expression of CD27 and CD70 in situ using multiplex immunofluorescence. CD27+ T-cell phenotypes in tumors were analyzed by flow cytometry and their gene expression profile were analyzed by single-cell RNA sequencing then confirmed with public data. Baseline sCD27 was measured in 81 patients with renal cell carcinoma (RCC) treated with immunotherapy (35 for training cohort and 46 for validation cohort). RESULTS: In the tumor microenvironment, CD27+ T cells interacted with CD70-expressing tumor cells. Compared with CD27- T cells, CD27+ T cells exhibited an apoptotic and dysfunctional signature. In patients with RCC, the intratumoral CD27-CD70 interaction was significantly correlated with the plasma sCD27 concentration. High sCD27 levels predicted poor overall survival in patients with RCC treated with anti-programmed cell death protein 1 in both the training and validation cohorts but not in patients treated with antiangiogenic therapy. CONCLUSIONS: In conclusion, we demonstrated that sCD27, a surrogate marker of T-cell dysfunction, is a predictive biomarker of resistance to immunotherapy in RCC. Given the frequent expression of CD70 and CD27 in solid tumors, our findings may be extended to other tumors.

Local administration of stem cell-derived extracellular vesicles in a thermoresponsive hydrogel promotes a pro-healing effect in a rat model of colo-cutaneous post-surgical fistula.

Extracellular vesicles (EVs), especially from stem/stromal cells (SCs), represent a cell-free alternative in regenerative medicine holding promises to promote tissue healing while providing safety and logistic advantages in comparison to cellular counterparts. Herein, we hypothesize that SC EVs, administered locally in a thermoresponsive gel, is a therapeutic strategy for managing post-surgical colo-cutaneous fistulas. This disease is a neglected and challenging condition associated to low remission rates and high refractoriness. Herein, EVs from a murine SC line were produced by a high-yield scalable method in bioreactors. The post-surgical intestinal fistula model was induced via a surgical cecostomy communicating the cecum and the skin in Wistar rats. Animals were treated just after cecostomy with PBS, thermoresponsive Pluronic F-127 hydrogel alone or containing SC EVs. A PET-monitored biodistribution investigation of SC EVs labelled with 89Zr was performed. Fistula external orifice and output assessment, probe-based confocal laser endomicroscopy, MRI and histology were carried out for therapy follow-up. The relevance of percutaneous EV administration embedded in the hydrogel vehicle was indicated by the PET-biodistribution study. Local administration of SC EVs in the hydrogel reduced colo-cutaneous fistula diameter, output, fibrosis and inflammation while increasing the density of neo-vessels when compared to the PBS and gel groups. This multi-modal investigation pointed-out the therapeutic potential of SC EVs administered locally and in a thermoresponsive hydrogel for the management of challenging post-surgical colon fistulas in a minimally-invasive cell-free strategy.

Long-Term Evaluation of Biliary Reflux on Esogastric Mucosae after One-Anastomosis Gastric Bypass and Esojejunostomy in Rats.

BACKGROUND: One-anastomosis gastric bypass/mini-gastric bypass (OAGB/MGB) remains controversial because it may cause chronic biliary reflux (BR). The risk of developing esogastric cancer due to BR after OAGB/MGB is based on the results of experimental rat studies using esojejunostomy (EJ). The aim of this study was to analyze the potential long-term consequences of BR on the esogastric mucosae in OAGB/MGB-operated rats and to compare these results to those from the use of EJ. METHODS: Wistar rats received OAGB/MGB (n = 16), EJ (n = 16), and sham (n = 8) operations. Mortality and weight changes were evaluated throughout the experiment. BR was measured using magnetic resonance imaging (MRI). Rats received follow-ups for 30 weeks. A double-blinded histological analysis was performed in the esogastric segments. RESULTS: BR was diagnosed in OAGB/MGB and EJ rats using the MRI technique; no BR occurred in the sham group. After a 30-week follow-up, no incidences of dysplasia or cancer were observed in the three groups. Additionally, esophageal intestinal metaplasia and mucosal ulcerations were observed in 41.7% and 50% of EJ rats, respectively, and no incidences of these conditions were observed in OAGB/MGB and sham rats. The incidence of esophagitis was significantly higher and more severe in the EJ group compared to those in the OAGB/MGB and sham groups (EJ = 100%, OAGB/MGB = 16.7%, sham = 8.3%; p < 0.001). CONCLUSIONS: After a 30-week follow-up period, OAGB/MGB rats did not develop any precancerous or cancerous lesions when more than 40% of EJ rats had intestinal metaplasia.

Immunotherapy in head and neck cancers: A new challenge for immunologists, pathologists and clinicians.

Cancer occurrence can be understood as the result of dysfunctions in immune tumoral microenvironment. Here we review the recent understandings of those microenvironment changes, regarding their causes and prognostic significance in head and neck (HN) carcinoma. We will focus on HN squamous cell cancer (SCC) and nasopharyngeal carcinomas (NPC). Their overall poor prognosis may be improved with immunotherapy in a subset of patients, as supported by current clinical trials. However, finding reliable markers of therapeutic response is crucial for patient selection, due to potential severe adverse reactions and high costs. Half of HNSCC exhibit PD-L1 expression, this expression being higher in HPV-positive tumors. In recent clinical trials, a better therapeutic response to anti-PD-1 was obtained in patients with higher PD-L1 expression. The Food and Drug Administration (FDA) approved the use of these therapeutics without stating a need for patient selection regarding PD-L1 status. Activation status, density and localization of TIL as well as PD-L2, γ-interferon, inflammatory cytokines, epithelial-mesenchymal transition phenotype and mutational burden may all be potential therapeutic response markers. In Epstein-Barr Virus (EBV)-induced nasopharyngeal non-keratinizing cancer, PD-L1 is over-expressed compared to EBV-negative tumors. A 22% response rate has been observed under anti-PD-1 treatment among PD-L1-positive NPC patients. A better understanding of immune checkpoint regulation processes may allow patients to benefit from these promising immunotherapies.