Artificial intelligence-based pathology as a biomarker of sensitivity to atezolizumab-bevacizumab in patients with hepatocellular carcinoma: a multicentre retrospective study.

BACKGROUND: Clinical benefits of atezolizumab plus bevacizumab (atezolizumab-bevacizumab) are observed only in a subset of patients with hepatocellular carcinoma and the development of biomarkers is needed to improve therapeutic strategies. The atezolizumab-bevacizumab response signature (ABRS), assessed by molecular biology profiling techniques, has been shown to be associated with progression-free survival after treatment initiation. The primary objective of our study was to develop an artificial intelligence (AI) model able to estimate ABRS expression directly from histological slides, and to evaluate if model predictions were associated with progression-free survival. METHODS: In this multicentre retrospective study, we developed a model (ABRS-prediction; ABRS-P), which was derived from the previously published clustering-constrained attention multiple instance learning (or CLAM) pipeline. We trained the model fit for regression analysis using a multicentre dataset from The Cancer Genome Atlas (patients treated by surgical resection, n=336). The ABRS-P model was externally validated on two independent series of samples from patients with hepatocellular carcinoma (a surgical resection series, n=225; and a biopsy series, n=157). The predictive value of the model was further tested in a series of biopsy samples from a multicentre cohort of patients with hepatocellular carcinoma treated with atezolizumab-bevacizumab (n=122). All samples in the study were from adults (aged ≥18 years). The validation sets were sampled between Jan 1, 2008, to Jan 1, 2023. For the multicentre validation set, the primary objective was to assess the association of high versus low ABRS-P values, defined relative to cross-validation median split thresholds in the first biopsy series, with progression-free survival after treatment initiation. Finally, we performed spatial transcriptomics and matched prediction heatmaps with in situ expression profiles. FINDINGS: Of the 840 patients sampled, 641 (76%) were male and 199 (24%) were female. Across the development and validation datasets, hepatocellular carcinoma risk factors included alcohol intake, hepatitis B and C virus infections, and non-alcoholic steatohepatitis. Using cross-validation in the development series, the mean Pearson's correlation between ABRS-P values and ABRS score (mean expression of ABRS genes) was r=0·62 (SD 0·09; mean p<0·0001, SD<0·0001). The ABRS-P generalised well on the external validation series (surgical resection series, r=0·60 [95% CI 0·51-0·68], p<0·0001; biopsy series, r=0·53 [0·40-0·63], p<0·0001). In the 122 patients treated with atezolizumab-bevacizumab, those with ABRS-P-high tumours (n=74) showed significantly longer median progression-free survival than those with ABRS-P-low tumours (n=48) after treatment initiation (12 months [95% CI 7-not reached] vs 7 months [4-9]; p=0·014). Spatial transcriptomics showed significantly higher ABRS score, along with upregulation of various other immune effectors, in tumour areas with high ABRS-P values versus areas with low ABRS-P values. INTERPRETATION: Our study indicates that AI applied on hepatocellular carcinoma digital slides is able to serve as a biomarker for progression-free survival in patients treated with atezolizumab-bevacizumab. This approach could be used in the development of inexpensive and fast biomarkers for targeted therapies. The combination of AI heatmaps with spatial transcriptomics provides insight on the molecular features associated with predictions. This methodology could be applied to other cancers or diseases and improve understanding of the biological mechanisms that drive responses to treatments. FUNDING: Institut National du Cancer, Fondation ARC, China Scholarship Council, Ligue Contre le Cancer du Val de Marne, Fondation de l'Avenir, Ipsen, and Fondation Bristol Myers Squibb Pour la Recherche en Immuno-Oncologie.

Longitudinal Study of Cirrhosis Development in STAM and carbon tetrachloride Mouse Models Using Fourier Transform Infrared Spectral Imaging.

Animal models of cirrhosis are of great interest to investigate the pathological process leading to the final stage of cirrhosis. The aim of this study was to analyze the different steps involved in the progressive development of cirrhosis using Fourier transform infrared spectral histology in 2 mouse models of cirrhosis, the STAM model of metabolic cirrhosis, and the carbon tetrachloride-induced cirrhosis model. Formalin-fixed, paraffin-embedded liver samples were obtained from 3 mice at 5 time points in each model to analyze the course of hepatic lesions up to the formation of cirrhosis. For each time point, adjacent 3-µm-thick liver sections were obtained for histologic stains and spectral histology. Fourier transform infrared acquisitions of liver sections were performed at projected pixel sizes of 25 µm × 25 µm and 6.25 µm × 6.25 µm. Spectral images were then preprocessed with an extended multiplicative signal correction and analyzed with common k-means clustering, including all stages in each model. In both models, the 2- and 4-class common k-means clustering in the 1000 to 1350 cm-1 range showed that spectral classes characterized by higher absorbance peaks of glycogen were predominant at baseline, then decreased markedly in early stages of hepatic damage, and almost disappeared in cirrhotic tissues. Concomitantly, spectral classes characterized by higher absorbance peaks of nucleic acids became progressively predominant during the course of hepatic lesions. These results were confirmed using k-means clustering on the peaks of interest identified for glycogen and nucleic acid content. Our study showed that the glycogen depletion previously described at the stage of cirrhosis is an early event in the pathological process, independently of the cause of cirrhosis. In addition, there was a progressive increase in the nucleic acid content, which may be linked to increased proliferation and polyploidy in response to cellular lesions.

Severe Libman-Sacks endocarditis complicating antiphospholipid syndrome: a retrospective analysis of 23 operated cases.

OBJECTIVE: Data on severe heart valve disease (HVD), including Libman-Sacks endocarditis, associated with SLE and/or APS requiring valvular surgery are scarce. We thus conducted a retrospective study, aimed at describing and clarifying clinical, laboratory, echocardiographic, histopathological and evolutional features of SLE and/or APS patients with severe associated-HVD. METHODS: An observational retrospective multicentric analysis of 23 adults with SLE and/or APS and HVD between 1996 and 2019 and available histopathological report evaluating long-term follow-up. RESULTS: Twenty-three individuals (20 females, median age 37 [range 17-76] years) were included. All had APS (thrombotic in 22, with an arterial phenotype in 15 and with catastrophic APS [CAPS] in six), and 11 (47%) had SLE. Systemic underlying disease had been diagnosed prior to HVD in 12 (52%). In 10 patients (43%), HVD was complicated by cerebral stroke prior to surgery. Twenty patients (87%) had only one pathological valve, the mitral valve in 18 patients (78%). Valvular thickening (n = 19) and valvular regurgitation (n = 19) were the most frequently reported lesions. Fifteen (62%) patients underwent mechanical valve replacement, six (26%) conservative valve repair (five were later re-operated after a median time of 1 [0-4] year), and two (9%) underwent biological valve replacement. Nine patients (39%) presented early-onset post-operative complications, including three CAPS immediately after surgery and one death. After surgery, 18 patients (78%) had normal postoperative valvular function, but almost half of the patients (43%) had post-operative neurological sequelae (median follow-up of 6 [2-20] years). CONCLUSION: Severe HVD leading to surgery was strongly associated with thrombotic APS, especially arterial phenotypes. Half of the reported patients presented cerebral stroke complicating the HVD. Valvular surgery carried a significant risk of CAPS.

Deep learning for the prediction of the chemotherapy response of metastatic colorectal cancer: comparing and combining H&E staining histopathology and infrared spectral histopathology.

Colorectal cancer is a global public health problem with one of the highest death rates. It is the second most deadly type of cancer and the third most frequently diagnosed in the world. The present study focused on metastatic colorectal cancer (mCRC) patients who had been treated with chemotherapy-based regimen for which it remains uncertainty about the efficacy for all eligible patients. This is a major problem, as it is not yet possible to test different therapies in view of the consequences on the health of the patients and the risk of progression. Here, we propose a method to predict the efficacy of an anticancer treatment in an individualized way, using a deep learning model constructed on the retrospective analysis of the primary tumor of several patients. Histological sections from tumors were imaged by standard hematoxylin and eosin (HE) staining and infrared spectroscopy (IR). Images obtained were then processed by a convolutional neural network (CNN) to extract features and correlate them with the subsequent progression-free survival (PFS) of each patient. Separately, HE and IR imaging resulted in a PFS prediction with an error of 6.6 and 6.3 months respectively (28% and 26% of the average PFS). Combining both modalities allowed to decrease the error to 5.0 months (21%). The inflammatory state of the stroma seemed to be one of the main features detected by the CNN. Our pilot study suggests that multimodal imaging analyzed with deep learning methods allow to give an indication of the effectiveness of a treatment when choosing.

[Drug induced gastro-intestinal tract lesions: A pathologist point of view]. / Lésions iatrogènes du tube digestif vues par le pathologiste.

The number of drugs available to clinicians, especially targeted therapies, grows continuously. Some drugs are known to cause frequent digestive adverse effects, which may affect the gastro-intestinal tract in a diffuse or localized manner. Some treatments may leave relatively pathognomonic deposits, but histological lesions of iatrogenic origin are mostly non-specific. The diagnostic and etiological approach is often complex because of these non-specific aspects and also because (1) a single type of drug may cause different histological lesions, (2) different drugs may cause identical histological lesions, (3) the patient may receive different drugs, and (4) drug-induced lesions may mimic other pathological entities such as inflammatory bowel disease, celiac disease, or graft versus host disease. The diagnosis of iatrogenic gastrointestinal tract injury therefore requires close anatomic-clinical correlation. The iatrogenic origin can only be formally established if the symptomatology improves when the incriminating drug is stopped. This review aims to present the different histological patterns of gastrointestinal tract iatrogenic lesions, the potentially incriminate drugs, as well as the histological signs to look for in order to help the pathologist to distinguish an iatrogenic injury from another pathology of the gastrointestinal tract.

[Inflammatory bowel diseases: Scoring and pathological reports optimization]. / Maladies inflammatoires chroniques intestinales : scores et optimisation des comptes rendus anatomopathologiques.

The two main forms of inflammatory bowel disease (IBD) are ulcerative colitis (UC) and Crohn's disease (CD). Both diseases have inflammatory flare-ups that alternate with periods of remission. The pathologist may examine biopsies of the digestive tract from IBD patients in different contexts: at the time of the initial diagnosis, in the event of a disease flare-up in order to differentiate a flare of the disease from another cause, particularly an infectious one, and during the long term follow-up of the disease in order to detect the occurrence of dysplastic lesions. Pathologists are increasingly involved in the evaluation of inflammatory activity during the follow-up of IBD patients. The therapeutic management of IBD has evolved significantly and the emergence of new treatments allows a global approach targeting endoscopic mucosal healing. However, mucosal healing is not always correlated with histological healing. Numerous studies have shown the value of histological evaluation during follow-up. A higher score for histological activity in ulcerative colitis predicts a higher likelihood of neoplasia. Histological activity is a better predictor than endoscopic inflammation of the risk. In UC, histological remission may be a long-term therapeutic goal but its role in CD remains unclear. Different scores have been developed to quantify the inflammatory activity of IBD patients and the response to treatment. The aim of this review is to present the main activity scores used in the follow-up of IBD, their interest, their evaluation and their limitations.

Nestin as a diagnostic and prognostic marker for combined hepatocellular-cholangiocarcinoma.

BACKGROUND & AIMS: Combined hepatocellular-cholangiocarcinoma (cHCC-CCA) is a rare primary liver cancer (PLC) associated with a poor prognosis. Given the challenges in its identification and its clinical implications, biomarkers are critically needed. We aimed to investigate the diagnostic and prognostic value of the immunohistochemical expression of Nestin, a progenitor cell marker, in a large multicentric series of PLCs. METHODS: We collected 461 cHCC-CCA samples from 32 different clinical centers. Control cases included 368 hepatocellular carcinomas (HCCs) and 221 intrahepatic cholangiocarcinomas (iCCAs). Nestin immunohistochemistry was performed on whole tumor sections. Diagnostic and prognostic performances of Nestin expression were determined using receiver-operating characteristic curves and Cox regression modeling. RESULTS: Nestin was able to distinguish cHCC-CCA from HCC with AUCs of 0.85 and 0.86 on surgical and biopsy samples, respectively. Performance was lower for the distinction of cHCC-CCA from iCCA (AUCs of 0.59 and 0.60). Nestin, however, showed a high prognostic value, allowing identification of the subset of cHCC-CCA ("Nestin High", >30% neoplastic cells with positive staining) associated with the worst clinical outcome (shorter disease-free and overall survival) after surgical resection and liver transplantation, as well as when assessment was performed on biopsies. CONCLUSION: We show in different clinical settings that Nestin has diagnostic value and that it is a useful biomarker to identify the subset of cHCC-CCA associated with the worst clinical outcome. Nestin immunohistochemistry may be used to refine risk stratification and improve treatment allocation for patients with this highly aggressive malignancy. LAY SUMMARY: There are different types of primary liver cancers (i.e. cancers that originate in the liver). Accurately identifying a specific subtype of primary liver cancer (and determining its associated prognosis) is important as it can have a major impact on treatment allocation. Herein, we show that a protein called Nestin could be used to refine risk stratification and improve treatment allocation for patients with combined hepatocellular carcinoma, a rare but highly aggressive subtype of primary liver cancer.

Automatic Identification of Paraffin Pixels on FTIR Images Acquired on FFPE Human Samples.

The transfer of mid-infrared spectral histopathology to the clinic will be possible provided that its application in clinical practice is simple. Rapid analysis of formalin-fixed paraffin-embedded (FFPE) tissue section is thus a prerequisite. The chemical dewaxing of these samples before image acquisition used by the majority of studies is in contradiction with this principle. Fortunately, the in silico analysis of the images acquired on FFPE samples is possible using extended multiplicative signal correction (EMSC). However, the removal of pure paraffin pixels is essential to perform a relevant classification of tissue spectra. So far, this task was possible only if using manual and subjective histogram analysis. In this article, we thus propose a new automatic and multivariate methodology based on the analysis of optimized combinations of EMSC regression coefficients by validity indices and KMeans clustering to separate paraffin and tissue pixels. The validation of our method is performed using simulated infrared spectral images by measuring the Jaccard index between our partitions and the image model, with values always over 0.90 for diverse baseline complexity and signal-to-noise ratio. These encouraging results were also validated on real images by comparing our method with classical ones and by computing the Jaccard index between our partitions and the KMeans partitions obtained on the infrared image acquired on the same samples but after chemical dewaxing, with values always over 0.84.

PD-L1 Expression in 65 Conjunctival Melanomas and Its Association with Clinical Outcome.

Conjunctival melanoma (CM) iss a rare and aggressive tumour that is increasing in frequency. The prognostic value of PD-L1 expression, alone or in combination with CD8 and PD-1 expression and the BRAF and NRAS status, has not been determined in CM to date. We evaluated the expression of PD-L1, CD8, PD-1 in CM and investigated whether there was an association between the expression of these markers and the BRAF and NRAS molecular profile as well as some clinico-pathological criteria. A total of sixty-five CM were assessed for PD-L1, PD-1, and CD8 expression by immunohistochemistry (IHC) and for BRAF and NRAS genomic alterations using molecular biology techniques and anti-BRAF and anti-NRAS antibodies. PD-L1 expression in tumour cells (TC) was very low or absent but detected in tumour-infiltrating immune cells (IC). A correlation was observed between the expression of PD-L1, CD8, and PD-1 in IC. No correlation between PD-L1 expression (in tumour and/or immune cells) and BRAF or NRAS mutations was observed. PD-L1 expression in IC correlated with a higher pTNM stage and PD-L1 expression in TC with worse disease-specific survival. PD-L1 expression is a potential prognostic biomarker that correlates with poor prognosis in CM patients.

Receptor for advanced glycation end products: a key molecule in the genesis of chronic kidney disease vascular calcification and a potential modulator of sodium phosphate co-transporter PIT-1 expression.

BACKGROUND: Chronic kidney disease (CKD) is associated with increased cardiovascular mortality, frequent vascular calcification (VC) and accumulation of uraemic toxins. Advanced glycation end products and S100 proteins interact with the receptor for advanced glycation end products (RAGE). In the present work, we aimed to investigate the role(s) of RAGE in the CKD-VC process. METHODS: Apoe-/- or Apoe-/-Ager (RAGE)-/- male mice were assigned to CKD or sham-operated groups. A high-phosphate diet was given to a subgroup of Apoe-/-and Apoe-/-Ager-/- CKD mice. Primary cultures of Ager+/+ and Ager-/- vascular smooth muscle cells (VSMCs) were established and stimulated with either vehicle, inorganic phosphate (Pi) or RAGE ligands (S100A12; 20 µM). RESULTS: After 12 weeks of CKD we observed a significant increase in RAGE ligand (AGE and S100 proteins) concentrations in the serum of CKD Apoe-/- mice. Ager messenger RNA (mRNA) levels were 4-fold higher in CKD vessels of Apoe-/- mice. CKD Apoe-/- but not CKD Apoe-/- or Ager-/- mice displayed a marked increase in the VC surface area. Similar trends were found in the high-phosphate diet condition. mRNA levels of Runx2 significantly increased in the Apoe-/- CKD group. In vitro, stimulation of Ager+/+VSMCs with Pi or S100A12 induced mineralization and osteoblast transformation, and this was inhibited by phosphonoformic acid (Pi co-transporters inhibitor) and Ager deletion. In vivo and in vitro RAGE was necessary for regulation of the expression of Pit-1, at least in part through production of reactive oxygen species. CONCLUSION: RAGE, through the modulation of Pit-1 expression, is a key molecule in the genesis of VC.

[Carcinoma cuniculatum: An unusual oral tumor]. / Carcinome cuniculatum : une tumeur orale inhabituelle.

We report on a case of carcinoma cuniculatum (CC) of the maxillary gingival mucosa. A 60-year-old woman presented with an exophytic gingivo-palatal mass with slow growth and osteolytic evolution. A first performed biopsy was negative for malignancy. The diagnosis of CC was established on the surgical representative biopsy. CC is a rare low-grade variant of squamous cell carcinoma that is usually found in the foot or in oral cavity. The pathognomonic microscopic feature of CC is an endo- and/or exophytic lesion composed by a well differentiated squamous epithelium infiltrating into underlying stroma forming a complex pattern of keratin cores and keratin filled "rabbit warren" crypts. CC is a locally evolutive carcinoma with a usually good prognosis usually without lymph node or distant metastatic evolution.

[Pathologist versus social media: A survival guide]. / Le pathologiste et les réseaux sociaux : mode d'emploi.

Social networks have changed the communication tools among healthcare professionals, enabling instantaneous and globalized sharing and monitoring of information. While more and more pathologists are taking advantage of these tools, some do not yet know them well, or have concerns about their use. These platforms have many advantages and the potential risks can be minimized by appropriate use. A pathologist community is very active, especially on Twitter and Facebook. They share and discuss interesting cases, communicate around our specialty or simply strengthen links between pathologists around the world. Professional organizations and pathology journals are also present. This article aims to present social networks, their pros and cons and to give some good practice tips and examples of uses of the 2 main social networks used in pathology: Facebook and Twitter.

Development and validation of the Nancy histological index for UC.

OBJECTIVE: We developed a validated index for assessing histological disease activity in UC and established its responsiveness. METHODS: Two hundred biopsies were scored. The outcome was the Global Visual Evaluation (GVE). Eight histological features were tested. The Nancy index was developed by multiple linear regression and bootstrap process to create an index that best matched the GVE. Goodness of fit was assessed by the adjusted R squared (adjusted R2). The second step was the validation of the index: 100 biopsies were scored for the Nancy index by three pathologists from different centres. Inter-reader reliability was evaluated for each reader. The relationship between the change of the Nancy index and the Geboes index was assessed to assess the responsiveness. RESULTS: After backward selection with bootstrap validation, 3/8 items were selected: ulceration (adjusted R2=0.55), acute inflammatory infiltrate (adjusted R2=0.88) and chronic inflammatory infiltrate (adjusted R2=0.79). The Nancy index is defined by a 5-level classification ranging from grade 0 (absence of significant histological disease activity) to grade 4 (severely active disease). The intraclass correlation coefficient (ICC) for the intrareader reliability was 0.88 (95% CI 0.82 to 0.92) and the index had good inter-reader reliability (ICC=0.86 (0.81 to 0.99)). The correlation between the Nancy index and the Geboes score or the GVE was very good. The index had a good responsiveness with a high correlation between changes in the Geboes score and changes in the Nancy index (0.910 (0.813 to 0.955)). CONCLUSIONS: A three descriptor histological index has been validated for use in clinical practice and clinical trials.

Signaling of Serum Amyloid A Through Receptor for Advanced Glycation End Products as a Possible Mechanism for Uremia-Related Atherosclerosis.

OBJECTIVE: Cardiovascular disease is the leading cause of death in patients with end-stage renal disease. Serum amyloid A (SAA) is an acute phase protein and a binding partner for the multiligand receptor for advanced glycation end products (RAGE). We investigated the role of the interaction between SAA and RAGE in uremia-related atherogenesis. APPROACH AND RESULTS: We used a mouse model of uremic vasculopathy, induced by 5 of 6 nephrectomy in the Apoe(-/-) background. Sham-operated mice were used as controls. Primary cultures of Ager(+/+) and Ager(-/-) vascular smooth muscle cells (VSMCs) were stimulated with recombinant SAA, S100B, or vehicle alone. Relevance to human disease was assessed with human VSMCs. The surface area of atherosclerotic lesions at the aortic roots was larger in uremic Apoe(-/-) than in sham-operated Apoe(-/-) mice (P<0.001). Furthermore, atherosclerotic lesions displayed intense immunostaining for RAGE and SAA, with a pattern similar to that of α-SMA. Ager transcript levels in the aorta were 6× higher in uremic animals than in controls (P<0.0001). Serum SAA concentrations were higher in uremic mice, not only after 4 weeks of uremia but also at 8 and 12 weeks of uremia, than in sham-operated animals. We investigated the functional role of RAGE in uremia-induced atherosclerosis further, in animals lacking RAGE. We found that the induction of uremia in Apoe(-/-) Ager(-/-) mice did not accelerate atherosclerosis. In vitro, the stimulation of Ager(+/+) but not of Ager(-/-) VSMCs with SAA or S100B significantly induced the production of reactive oxygen species, the phosphorylation of AKT and mitogen-activated protein kinase-extracellular signal-regulated kinases and cell migration. Reactive oxygen species inhibition with N-acetyl cysteine significantly inhibited both the phosphorylation of AKT and the migration of VSMCs. Similar results were obtained for human VSMCs, except that the phosphorylation of mitogen-activated protein kinase-extracellular signal-regulated kinases, rather than of AKT, was subject to specific redox-regulation by SAA and S100B. Furthermore, human aortic atherosclerotic sections were positively stained for RAGE and SAA. CONCLUSIONS: Uremia upregulates SAA and RAGE expression in the aortic wall and in atherosclerotic lesions in mice. Ager(-/-) animals are protected against the uremia-induced acceleration of atherosclerosis. SAA modulates the functions of murine and human VSMCs in vitro in a RAGE-dependent manner. This study, therefore, identifies SAA as a potential new uremic toxin involved in uremia-related atherosclerosis through interaction with RAGE.

Collagen-Based Medical Device as a Stem Cell Carrier for Regenerative Medicine.

Maintenance of mesenchymal stem cells (MSCs) requires a tissue-specific microenvironment (i.e., niche), which is poorly represented by the typical plastic substrate used for two-dimensional growth of MSCs in a tissue culture flask. The objective of this study was to address the potential use of collagen-based medical devices (HEMOCOLLAGENE®, Saint-Maur-des-Fossés, France) as mimetic niche for MSCs with the ability to preserve human MSC stemness in vitro. With a chemical composition similar to type I collagen, HEMOCOLLAGENE® foam presented a porous and interconnected structure (>90%) and a relative low elastic modulus of around 60 kPa. Biological studies revealed an apparently inert microenvironment of HEMOCOLLAGENE® foam, where 80% of cultured human MSCs remained viable, adopted a flattened morphology, and maintained their undifferentiated state with basal secretory activity. Thus, three-dimensional HEMOCOLLAGENE® foams present an in vitro model that mimics the MSC niche with the capacity to support viable and quiescent MSCs within a low stiffness collagen I scaffold simulating Wharton's jelly. These results suggest that haemostatic foam may be a useful and versatile carrier for MSC transplantation for regenerative medicine applications.

Comparing histological activity indexes in UC.

BACKGROUND: Assessment of disease activity in UC is important for designing an optimal therapeutic strategy. No single histology score is considered optimum. The aim of this study was to compare intraobserver reproducibility and the interobserver agreement of available histological UC activity indexes. METHODS: One hundred and two biopsy specimens (collected between 2003 and 2014) were scored blindly by three pathologists by determining Geboes, Riley, Gramlich and Gupta indexes and global visual evaluation (GVE). Intraobserver reproducibility and interobserver agreements for index and items of index were studied by intraclass correlation coefficient for quantitative parameter and by κ values and Krippendorff index for qualitative parameters. Relationship between indexes was studied by computation of Pearson's and Spearman's correlation coefficients. RESULTS: Geboes, Riley, Gramlich and Gupta indexes and GVE showed good intraobserver reproducibility and a good interobserver agreement. Histological items that showed the best interobserver agreement were 'erosion/ulceration or surface epithelial integrity' and 'acute inflammatory cells infiltrate/neutrophils in lamina propria'. The five scores were strongly correlated. CONCLUSIONS: Correlation between indexes is strong. Intraobserver reproducibility and interobserver agreement for all indexes is very good. Histological items that showed the best interobserver agreement are 'erosion/ulceration' and 'acute inflammatory cells infiltrate/neutrophils in lamina propria'.