Fully Automated Tumor Bud Assessment in Hematoxylin and Eosin-Stained Whole Slide Images of Colorectal Cancer.

Tumor budding (TB), the presence of single cells or small clusters of up to 4 tumor cells at the invasive front of colorectal cancer (CRC), is a proven risk factor for adverse outcomes. International definitions are necessary to reduce interobserver variability. According to the current international guidelines, hotspots at the invasive front should be counted in hematoxylin and eosin (H&E)-stained slides. This is time-consuming and prone to interobserver variability; therefore, there is a need for computer-aided diagnosis solutions. In this study, we report an artificial intelligence-based method for detecting TB in H&E-stained whole slide images. We propose a fully automated pipeline to identify the tumor border, detect tumor buds, characterize them based on the number of tumor cells, and produce a TB density map to identify the TB hotspot. The method outputs the TB count in the hotspot as a computational biomarker. We show that the proposed automated TB detection workflow performs on par with a panel of 5 pathologists at detecting tumor buds and that the hotspot-based TB count is an independent prognosticator in both the univariate and the multivariate analysis, validated on a cohort of n = 981 patients with CRC. Computer-aided detection of tumor buds based on deep learning can perform on par with expert pathologists for the detection and quantification of tumor buds in H&E-stained CRC histopathology slides, strongly facilitating the introduction of budding as an independent prognosticator in clinical routine and clinical trials.

Computer-Assisted Diagnosis of Lymph Node Metastases in Colorectal Cancers Using Transfer Learning With an Ensemble Model.

Screening of lymph node metastases in colorectal cancer (CRC) can be a cumbersome task, but it is amenable to artificial intelligence (AI)-assisted diagnostic solution. Here, we propose a deep learning-based workflow for the evaluation of CRC lymph node metastases from digitized hematoxylin and eosin-stained sections. A segmentation model was trained on 100 whole-slide images (WSIs). It achieved a Matthews correlation coefficient of 0.86 (±0.154) and an acceptable Hausdorff distance of 135.59 µm (±72.14 µm), indicating a high congruence with the ground truth. For metastasis detection, 2 models (Xception and Vision Transformer) were independently trained first on a patch-based breast cancer lymph node data set and were then fine-tuned using the CRC data set. After fine-tuning, the ensemble model showed significant improvements in the F1 score (0.797-0.949; P <.00001) and the area under the receiver operating characteristic curve (0.959-0.978; P <.00001). Four independent cohorts (3 internal and 1 external) of CRC lymph nodes were used for validation in cascading segmentation and metastasis detection models. Our approach showed excellent performance, with high sensitivity (0.995, 1.0) and specificity (0.967, 1.0) in 2 validation cohorts of adenocarcinoma cases (n = 3836 slides) when comparing slide-level labels with the ground truth (pathologist reports). Similarly, an acceptable performance was achieved in a validation cohort (n = 172 slides) with mucinous and signet-ring cell histology (sensitivity, 0.872; specificity, 0.936). The patch-based classification confidence was aggregated to overlay the potential metastatic regions within each lymph node slide for visualization. We also applied our method to a consecutive case series of lymph nodes obtained over the past 6 months at our institution (n = 217 slides). The overlays of prediction within lymph node regions matched 100% when compared with a microscope evaluation by an expert pathologist. Our results provide the basis for a computer-assisted diagnostic tool for easy and efficient lymph node screening in patients with CRC.

Pathologist Computer-Aided Diagnostic Scoring of Tumor Cell Fraction: A Swiss National Study.

Tumor cell fraction (TCF) estimation is a common clinical task with well-established large interobserver variability. It thus provides an ideal test bed to evaluate potential impacts of employing a tumor cell fraction computer-aided diagnostic (TCFCAD) tool to support pathologists' evaluation. During a National Slide Seminar event, pathologists (n = 69) were asked to visually estimate TCF in 10 regions of interest (ROIs) from hematoxylin and eosin colorectal cancer images intentionally curated for diverse tissue compositions, cellularity, and stain intensities. Next, they re-evaluated the same ROIs while being provided a TCFCAD-created overlay highlighting predicted tumor vs nontumor cells, together with the corresponding TCF percentage. Participants also reported confidence levels in their assessments using a 5-tier scale, indicating no confidence to high confidence, respectively. The TCF ground truth (GT) was defined by manual cell-counting by experts. When assisted, interobserver variability significantly decreased, showing estimates converging to the GT. This improvement remained even when TCFCAD predictions deviated slightly from the GT. The standard deviation (SD) of the estimated TCF to the GT across ROIs was 9.9% vs 5.8% with TCFCAD (P < .0001). The intraclass correlation coefficient increased from 0.8 to 0.93 (95% CI, 0.65-0.93 vs 0.86-0.98), and pathologists stated feeling more confident when aided (3.67 ± 0.81 vs 4.17 ± 0.82 with the computer-aided diagnostic [CAD] tool). TCFCAD estimation support demonstrated improved scoring accuracy, interpathologist agreement, and scoring confidence. Interestingly, pathologists also expressed more willingness to use such a CAD tool at the end of the survey, highlighting the importance of training/education to increase adoption of CAD systems.

Image-based assessment of extracellular mucin-to-tumor area predicts consensus molecular subtypes (CMS) in colorectal cancer.

The backbone of all colorectal cancer classifications including the consensus molecular subtypes (CMS) highlights microsatellite instability (MSI) as a key molecular pathway. Although mucinous histology (generally defined as >50% extracellular mucin-to-tumor area) is a "typical" feature of MSI, it is not limited to this subgroup. Here, we investigate the association of CMS classification and mucin-to-tumor area quantified using a deep learning algorithm, and  the expression of specific mucins in predicting CMS groups and clinical outcome. A weakly supervised segmentation method was developed to quantify extracellular mucin-to-tumor area in H&E images. Performance was compared to two pathologists' scores, then applied to two cohorts: (1) TCGA (n = 871 slides/412 patients) used for mucin-CMS group correlation and (2) Bern (n = 775 slides/517 patients) for histopathological correlations and next-generation Tissue Microarray construction. TCGA and CPTAC (n = 85 patients) were used to further validate mucin detection and CMS classification by gene and protein expression analysis for MUC2, MUC4, MUC5AC and MUC5B. An excellent inter-observer agreement between pathologists' scores and the algorithm was obtained (ICC = 0.92). In TCGA, mucinous tumors were predominantly CMS1 (25.7%), CMS3 (24.6%) and CMS4 (16.2%). Average mucin in CMS2 was 1.8%, indicating negligible amounts. RNA and protein expression of MUC2, MUC4, MUC5AC and MUC5B were low-to-absent in CMS2. MUC5AC protein expression correlated with aggressive tumor features (e.g., distant metastases (p = 0.0334), BRAF mutation (p < 0.0001), mismatch repair-deficiency (p < 0.0001), and unfavorable 5-year overall survival (44% versus 65% for positive/negative staining). MUC2 expression showed the opposite trend, correlating with less lymphatic (p = 0.0096) and venous vessel invasion (p = 0.0023), no impact on survival.The absence of mucin-expressing tumors in CMS2 provides an important phenotype-genotype correlation. Together with MSI, mucinous histology may help predict CMS classification using only histopathology and should be considered in future image classifiers of molecular subtypes.

A combined spatial score of granzyme B and CD68 surpasses CD8 as an independent prognostic factor in TNM stage II colorectal cancer.

BACKGROUND: Previous assessments of peritumoral inflammatory infiltrate in colorectal cancer (CRC) have focused on the role of CD8+ T lymphocytes. We sought to compare the prognostic value of CD8 with downstream indicators of active immune cell function, specifically granzyme B (GZMB) and CD68 in the tumour microenvironment. METHODS: Immunohistochemical (IHC) staining was performed for CD8, GZMB, CD68 and CD163 on next-generation tissue microarrays (ngTMAs) in a primary cohort (n = 107) and a TNM stage II validation cohort (n = 151). Using digital image analysis, frequency of distinct immune cell types was calculated for tumour proximity (TP) zones with varying radii (10 µm-100 µm) around tumour cells. RESULTS: Associations notably of advanced TNM stage were observed for low density of CD8 (p = 0.002), GZMB (p < 0.001), CD68 (p = 0.034) and CD163 (p = 0.011) in the primary cohort. In the validation cohort only low GZMB (p = 0.036) was associated with pT4 stage. Survival analysis showed strongest prognostic effects in the TP25µm zone at the tumour centre for CD8, GZMB and CD68 (all p < 0.001) in the primary cohort and for CD8 (p = 0.072), GZMB (p = 0.035) and CD68 (p = 0.004) in the validation cohort with inferior prognostic effects observed at the tumour invasive margin. In a multivariate survival analysis, joint analysis of GZMB and CD68 was similarly prognostic to CD8 in the primary cohort (p = 0.007 vs. p = 0.002) and superior to CD8 in the validation cohort (p = 0.005 vs. p = 0.142). CONCLUSION: Combined high expression of GZMB and CD68 within 25 µm to tumour cells is an independent prognostic factor in CRC and of superior prognostic value to the well-established CD8 in TNM stage II cancers. Thus, assessment of antitumoral effect should consider the quality of immune activation in peritumoral inflammatory cells and their actual proximity to tumour cells.

Atypical Pleomorphic Lipomatous Tumor of the Right Hand Mimicing Venous Malformation.

We present the case of a 31-year-old woman who was referred with a 12-month history of a tumor on the ulnar side of her dominant right hand. The eventual histopathologic diagnosis was an atypical pleomorphous lipomatous tumor, an entity that has only been recently classified in the World Health Organization Classification of Soft Tissue and Bone Tumors.

[Tumor budding in colorectal cancer-Information for clinical use and instructions for practical evaluation]. / Tumor Budding beim kolorektalen Karzinom ­ Informationen zur klinischen Anwendung und Anleitung zur praktischen Bestimmung.

BACKGROUND: Some patients with high-risk colorectal cancer show a worse prognosis within the same UICC stage. Therefore, the identification of additional risk factors is necessary to find the best treatment for these patients. OBJECTIVE: In which settings can tumor budding help the clinical decision-making process for treatment planning and how should scoring be performed? MATERIAL AND METHODS: Evaluation of current publications on tumor budding with an emphasis on practical grading and potential problems in the determination of tumor budding. RESULTS: Tumor budding is a significant risk factor for worse clinical outcome of colorectal cancer and can influence clinical decision-making in pT1 and stage II colorectal cancer. A scoring method was standardized by the ITBCC 2016 and is feasible in everyday practice. Challenges in assessment can be addressed by increasing awareness of potential problem cases.

Taking tumour budding to the next frontier - a post International Tumour Budding Consensus Conference (ITBCC) 2016 review.

Tumour budding in colorectal cancer, defined as single tumour cells or small clusters containing four or fewer tumour cells, is a robust and independent biomarker of aggressive tumour biology. On the basis of published data in the literature, the evidence is certainly in favour of reporting tumour budding in routine practice. One important aspect of implementing tumour budding has been to establish a standardised and evidence-based scoring method, as was recommended by the International Tumour Budding Consensus Conference (ITBCC) in 2016. Further developments have aimed at establishing methods for automated tumour budding assessment. A digital approach to scoring tumour buds has great potential to assist in performing an objective budding count but, like the manual consensus method, must be validated and standardised. The aim of the present review is to present general considerations behind the ITBCC scoring method, and a broad overview of the current situation and challenges regarding automated tumour budding detection methods.

Tumour budding and CD8+ T cells: 'attackers' and 'defenders' in rectal cancer with and without neoadjuvant chemoradiotherapy.

AIM: Tumour budding ('attacker') and CD8+ T cells ('defender') are recognised as important parameters for risk stratification in colon cancers and, combined, may have an even stronger clinical impact. Here, we determine the value of tumour budding and CD8+ in rectal cancer patients treated with/without neoadjuvant therapy. METHODS AND RESULTS: Using digital scans of all tumour slides/case, we analysed CD8+ T cell counts in two patient cohorts: 45 neoadjuvantly treated and 47 primarily surgically treated (totalling n = 543 slides) after double-staining of the surgical resection specimen for pan-cytokeratin and CD8+ . Tumour buds in hot-spots were manually counted (area = 0.785 mm2 ) and CD8+ T cell counts were analysed separately both in tumour budding hot-spots and the densest CD8+ regions throughout the tumour. In neoadjuvantly treated patients, only tumour budding and not CD8+ T cells was associated with tumour features, including more advanced ypT (P = 0.0062), venous invasion (P = 0.002), lymphatic invasion (P = 0.0003) and perineural invasion (P = 0.0017), as well as higher American Joint Committee on Cancer (AJCC) tumour regression score (P = 0.0035), indicating less tumour response. Overall survival was also worse in patients with high-grade budding in univariate analysis only. In contrast, all three variables, namely tumour budding (P = 0.0347), CD8+ T cells in budding hot-spots (P = 0.0382) and CD8+ T cells in the densest areas (P = 0.0117) were also associated with worse (budding) and better (CD8) survival time in the multivariate setting. CONCLUSION: In rectal cancer, tumour budding has clinical relevance in both primarily surgically treated patients and in those with neoadjuvantly treated patients, where it characterises highly aggressive residual disease. CD8+ T cell counts appear not to have prognostic relevance in the neoadjuvant context.

Metastasizing chondroblastoma: a rare bone tumor no longer supported by the WHO classification.

According to the World Health Organization (WHO) classification, tumors showing hematogenous spread in less than 2% of cases are categorized as "rarely metastasizing" and constitute a group of neoplasms of intermediate malignancy. Since its introduction in 2002, chondroblastoma has been considered one of the prototypic examples of this category of lesions. In the fifth and only recently published edition of the WHO classification of bone and soft tissue tumors, however, chondroblastoma was re-classified from rarely metastasizing to benign due to the rarity of cases with systemic spread. Here, we present a remarkable case of a 54-year-old male who presented with an expansile tumor in his left acromion that was diagnosed as chondroblastoma following biopsy. Three years later a local recurrence was noted during routine follow-up and a bone scan detected hypermetabolic lesions in a rib and the thoracic spine. Over time, he developed multifocal skeletal spread as well as soft tissue and pulmonary metastases, which histologically all revealed conventional chondroblastoma morphology and the highly specific H3-3B point mutation (p.Lys36Met). Thirteen years after initial diagnosis he is currently treated with experimental immunotherapy and shows stable but disseminated disease. Our case highlights that although metastasizing chondroblastoma is rare, potential systemic spread should be kept in mind in patients with chondroblastoma despite the new WHO classification.

[The autopsy of Napoleon Bonaparte: Anatomo-pathological assessment for the bicentenary of the death of Napoleon I on the island of Saint Helena in 1821]. / L'autopsie de Napoléon Bonaparte. Mise au point anatomo-pathologique pour le bicentenaire de la mort de Napoléon Ier sur l'île de Sainte-Hélène en 1821.

Napoleon Bonaparte died on 5 May 1821 on the island of St Helena after almost six years of exile. The next day, Dr Francesco Antommarchi, a Corsican doctor chosen by the Bonaparte family to treat the exiled emperor, performed the autopsy in the presence of sixteen people, including seven British doctors. Two hundred years after the event of 6 May 1821, the cause of Napoleon's death is still a mystery. Various hypotheses, such as arsenic intoxication, cardiac arrhythmia or, more recently, anaemia caused by gastrointestinal haemorrhage associated with chronic gastritis, have been put forward in the medical-historical literature. The main reasons for all these debates and misunderstandings are the presence of several autopsy reports, their often unscientific interpretation, as well as a certain taste for mystery. However, from a scientific point of view, the question arises as to whether autopsy reports are really conclusive as to the real cause of death. Thus, on the occasion of the bicentenary of Napoleon I's death in St. Helena, an international group of anatomo-pathologists specialising in digestive pathology set themselves the goal of analysing Napoleon I's autopsy reports according to their level of medical evidence (high, moderate and low). The autopsy reports of 1821 support the hypothesis of advanced malignant neoplasia of the stomach associated with gastric haemorrhage as the immediate cause of Napoleon I's death on 5 May 1821.

Remote area nurses' perceptions of the enablers and barriers for delivering end-of-life care in remote Australia to Aboriginal people who choose to pass away on their traditional lands.

INTRODUCTION: This research was undertaken to gain insight into what remote area nurses perceived were enablers and barriers to being involved in delivering care to an Aboriginal person with a terminal diagnosis passing away on their traditional lands. It is hoped that this gives remote area nurses, Aboriginal Australians and service providers a glimpse into what is happening in the remote areas of Australia. Remote area nurses often work in isolated and in extreme geographical locations. This also means that a significant proportion work alongside and with Aboriginal Australians. In addition, remote area nurses are often left to support people in the communities they work in under extreme and often under-resourced conditions. METHODS: A literature review was undertaken on this subject and a four-section questionnaire was then developed based on the literature. This included demographic questions and two sections using an ordinal Likert scale. The Likert scale questions asked remote area nurses about the skills they felt they used to deal with particular situations and the capacity of the health service to deal with the situations. The fourth section comprised open-ended questions. Thematic analysis was undertaken on the open-ended questions. Categories and themes were developed, and the results discussed. The four-part questionnaire was designed to be anonymous, and it formed part of the questionnaire distributed to students enrolled with the School of Indigenous and Remote Health Alice Springs, Flinders University by email, and to not-for-profit membership organisation CRANAplus for distribution through their networks. RESULTS: Remote area nurses felt that the barriers to supporting an Aboriginal Australian with a terminal diagnosis passing away on their traditional lands were a lack of support around the delivery of culturally appropriate end-of-life care, lack of a stable workforce, insufficient cultural knowledge and understanding, and a lack of guidance and support from family. They felt the enablers were effective communication with the family and Aboriginal elders providing advice to staff and direction on how they can support the family, willingness of staff to participate in care, and input from Aboriginal health practitioners. CONCLUSION: Remote area nurses perceived they lacked support and knowledge from several different areas, both from within their communities and outside of their communities. Despite the barriers, it was evident that remote area nurses can be very resourceful at enabling the processes of supporting Aboriginal people with a terminal diagnosis passing away on their traditional lands.

Tumour budding/T cell infiltrates in colorectal cancer: proposal of a novel combined score.

AIMS: The tumour-node-metastasis classification system is used for prognostication purposes and to guide patient management. However, in colorectal cancer (CRC), additional markers are needed to stratify prognostic subgroups. Two promising markers have emerged from large bodies of research: tumour budding and T cell host response (CD3, CD8 and CD45RO infiltrates). However, attempts to combine these two parameters have been sparse. The aim of this study was to perform an assessment of potential protagonists that could be used in a combined score (budding/T cell score, BTS). METHODS AND RESULTS: This descriptive, retrospective study was performed on a multipunch tissue microarray containing material from 345 patients with stages I-IV CRC. Areas from tumour centre, front and microenvironment were stained for pancytokeratin/CD3, pancytokeratin/CD8 and pancytokeratin/CD45RO. Tumour buds were scored manually and T cell infiltrates digitally using open-source software. Tumour buds, T cell counts and combined BTS were associated with clinicopathological features and overall survival (OS). A higher combined BTS score (buds/CD8, tumour centre) performed better than budding or CD8/CD3 alone in predicting nodal metastases (P < 0.0001, OR = 1.466, 95% CI = 1.115-1.928). Only higher BTS (buds/CD3) were significantly associated with poorer OS on multivariate analysis (P = 0.012, hazard ratio = 1.218, 95% confidence interval = 1.044-1.419). CONCLUSIONS: Although CD8+ /CD3+ T cells are predictive of tumour biology in CRC, we found a combined BTS to be stronger in predicting survival and certain features with high clinical relevance, such as nodal metastases, in comparison to budding or T cells alone. Further studies combining T cell infiltrates and tumour budding are necessary to optimise risk assessment of CRC.

Tumour budding is associated with the mesenchymal colon cancer subtype and RAS/RAF mutations: a study of 1320 colorectal cancers with Consensus Molecular Subgroup (CMS) data.

BACKGROUND: Tumour budding is an important prognostic factor in colorectal cancer (CRC). Molecular profiling of tumour buds suggests (partial) epithelial-mesenchymal transition and cancer stem-cell phenotype, similarly described in the "mesenchymal" Consensus Molecular Subtype 4 (CMS4), which identifies a particularly poor prognostic subgroup. Here, we determine the association of tumour budding with CMS classification, prognosis, and response to therapy. METHODS: AMC-AJCCII-90 cohort (n = 76, stage II) was evaluated for peritumoural budding on H&E slides. LUMC (n = 270, stage I-IV), CAIRO (n = 504, metastatic CRC) and CAIRO2 (n = 472, metastatic CRC) cohorts were investigated for intratumoural budding using pan-cytokeratin-stained tissue microarrays. Budding was scored as count/area, then classified as <5 or ≥5 buds. For all cohorts, CMS classifications were available (gene-expression/immunohistochemistry-based classifiers). RESULTS: High (≥5) budding predicted a worse outcome in multivariate analysis in AMC-AJCCII-90 (p = 0.018), LUMC (p < 0.0001), and CAIRO (p = 0.03), and in CAIRO2 (continuous variable, p = 0.02). Tumour budding counts were higher in CMS4 compared to epithelial CMS2/3 cancers (p < 0.01, all), and associated with KRAS/BRAF mutations (p < 0.01, AMC-AJCCII-90, CAIRO, CAIRO2). CONCLUSION: Tumour budding is an adverse prognostic factor across all CRC stages and is associated with the mesenchymal CMS4 phenotype. KRAS/BRAF mutations are strongly correlated with tumour budding suggesting their involvement in the regulation of this process.

[Current standards of pathological and molecular diagnostics in colorectal cancer]. / Standards der histopathologischen und molekularen Diagnostik des kolorektalen Karzinoms.

Current standards of pathological and molecular diagnostics in colorectal cancer Abstract. The pathologic assessment of biopsy and resections specimens plays an important role for further management of colorectal cancer patients. Therefore, careful evaluation of certain prognostic and predictive factors is crucial to ensure optimized and individualized patient care. In addition, progress in treatment options which require molecular diagnostics have led to integration of such tests in routine. The aim of this review is to provide a concise and pragmatic summary of the most important prognostic and predictive biomarkers currently in used for high-quality pathological analysis of colorectal cancer.

Recommendations for reporting tumor budding in colorectal cancer based on the International Tumor Budding Consensus Conference (ITBCC) 2016.

Tumor budding is a well-established independent prognostic factor in colorectal cancer but a standardized method for its assessment has been lacking. The primary aim of the International Tumor Budding Consensus Conference (ITBCC) was to reach agreement on an international, evidence-based standardized scoring system for tumor budding in colorectal cancer. The ITBCC included nine sessions with presentations, a pre-meeting survey and an e-book covering the key publications on tumor budding in colorectal cancer. The 'Grading of Recommendation Assessment, Development and Evaluation' method was used to determine the strength of recommendations and quality of evidence. The following 10 statements achieved consensus: tumor budding is defined as a single tumor cell or a cell cluster consisting of four tumor cells or less (22/22, 100%). Tumor budding is an independent predictor of lymph node metastases in pT1 colorectal cancer (23/23, 100%). Tumor budding is an independent predictor of survival in stage II colorectal cancer (23/23, 100%). Tumor budding should be taken into account along with other clinicopathological features in a multidisciplinary setting (23/23, 100%). Tumor budding is counted on H&E (19/22, 86%). Intratumoral budding exists in colorectal cancer and has been shown to be related to lymph node metastasis (22/22, 100%). Tumor budding is assessed in one hotspot (in a field measuring 0.785 mm2) at the invasive front (22/22, 100%). A three-tier system should be used along with the budding count in order to facilitate risk stratification in colorectal cancer (23/23, 100%). Tumor budding and tumor grade are not the same (23/23, 100%). Tumor budding should be included in guidelines/protocols for colorectal cancer reporting (23/23, 100%). Members of the ITBCC were able to reach strong consensus on a single international, evidence-based method for tumor budding assessment and reporting. It is proposed that this method be incorporated into colorectal cancer guidelines/protocols and staging systems.

Comprehensive assessment of tumour budding by cytokeratin staining in colorectal cancer.

AIMS: Tumour budding in colorectal cancer (CRC) is a recognized prognostic parameter. The aim of this study was to address the use of cytokeratin immunostaining for the visualization and scoring of tumour buds. METHODS AND RESULTS: Ten hotspots (0.238 mm2 ) of peritumoural budding (PTB) and intratumoural budding (ITB) were evaluated in surgical resections from 215 patients. The budding counts in the 10 densest regions anywhere in the tumour were combined into an overall tumour budding (OTB) score. The PTB, ITB and OTB hotspot with the maximum budding count was then evaluated. Finally, continuous and cut-off values of 10 buds per high-power field (HPF) (PTB10HPF ), five buds per HPF (ITB10HPF ) and eight buds per HPF (OTB10HPF ) were used to categorize budding counts into low-grade and high-grade scores. All budding scores were highly correlated. PTB and ITB counts were associated with many clinicopathological features, including tumour stage, lymph node and distant metastasis, venous and lymphovascular invasion, and disease-free survival (DFS) (all P < 0.05). Analyses of OTB counts recapitulated these associations, including a lower DFS with a greater number of tumour buds (P = 0.0309; hazard ratio 1.0332, 95% confidence interval 1.003-1.062). One OTB hotspot performed similarly to 10 OTB hotspots in terms of relationship with outcome. These statistical significances were largely lost when cut-offs were applied to PTB, ITB or OTB counts. CONCLUSIONS: An OTB count in a single hotspot on cytokeratin-stained CRC tissue sections is a fast and reliable prognostic scoring system for the assessment of tumour budding. This approach should be considered in future studies.

HtrA3 stromal expression is correlated with tumor budding in stage II colorectal cancer.

Tumor budding is a well-established adverse prognostic factor in colorectal carcinoma (CRC). It may represent a form of epithelial-to-mesenchymal transition (EMT), although the underlying mechanisms remain unclear. High-temperature requirement A3 (HtrA3) is an inhibitor of the bone morphogenetic protein pathway, the suppression of which has been linked to EMT. Since HtrA3 is highly expressed in the desmoplastic stroma at the CRC invasive front, we sought to evaluate the relationship between tumor budding and HtrA3 expression in 172 stage II CRC resection specimens. All tumors were evaluated for tumor budding, with the highest budding slide selected for pan-keratin (CK) and HtrA3 immunohistochemistry. Representative areas of tumor core and invasive front, including budding and non-budding areas, were marked on CK stained slides, and then evaluated on HtrA3 stained slides. HtrA3 expression in tumor cells (tHtrA3) and peritumoral stroma (sHtrA3) was assessed for staining percentage and intensity (the product yielding a final score). Tumors with high-grade tumor budding (HGTB) showed increased expression of sHtrA3 in budding areas compared to non-budding areas at the invasive front (P<0.001). In addition, sHtrA3 expression at the invasive front was significantly higher in HGTB tumors compared to minimally budding tumors (P<0.05). tHtrA3 expression at the invasive front was significantly associated with high histological grade (P<0.05). Higher sHtrA3 expression in the tumor core (but not invasive front) was significantly associated with decreased 5-year overall survival on univariate analysis (P<0.05), but not multivariate analysis. HtrA3 expression in the peritumoral stroma of patients with stage II CRC is associated with HGTB and may be a novel marker of poor outcome.

Tumour border configuration in colorectal cancer: proposal for an alternative scoring system based on the percentage of infiltrating margin.

AIMS: Information on tumour border configuration (TBC) in colorectal cancer (CRC) is currently not included in most pathology reports, owing to lack of reproducibility and/or established evaluation systems. The aim of this study was to investigate whether an alternative scoring system based on the percentage of the infiltrating component may represent a reliable method for assessing TBC. METHODS AND RESULTS: Two hundred and fifteen CRCs with complete clinicopathological data were evaluated by two independent observers, both 'traditionally' by assigning the tumours into pushing/infiltrating/mixed categories, and alternatively by scoring the percentage of infiltrating margin. With the pushing/infiltrating/mixed pattern method, interobserver agreement (IOA) was moderate (κ = 0.58), whereas with the percentage of infiltrating margins method, IOA was excellent (intraclass correlation coefficient of 0.86). A higher percentage of infiltrating margin correlated with adverse features such as higher grade (P = 0.0025), higher pT (P = 0.0007), pN (P = 0.0001) and pM classification (P = 0.0063), high-grade tumour budding (P < 0.0001), lymphatic invasion (P < 0.0001), vascular invasion (P = 0.0032), and shorter survival (P = 0.0008), and was significantly associated with an increased probability of lymph node metastasis (P < 0.001). CONCLUSIONS: Information on TBC gives additional prognostic value to pathology reports on CRC. The novel proposed scoring system, by using the percentage of infiltrating margin, outperforms the 'traditional' way of reporting TBC. Additionally, it is reproducible and simple to apply, and can therefore be easily integrated into daily diagnostic practice.

Tyrosine kinase receptor B (TrkB) expression in colorectal cancers highlights anoikis resistance as a survival mechanism of tumour budding cells.

AIMS: Tumour buds in colorectal cancer represent an aggressive subgroup of non-proliferating and non-apoptotic tumour cells. We hypothesize that the survival of tumour buds is dependent upon anoikis resistance. The role of tyrosine kinase receptor B (TrkB), a promoter of epithelial-mesenchymal transition and anoikis resistance, in facilitating budding was investigated. METHODS AND RESULTS: Tyrosine kinase receptor B immunohistochemistry was performed on a multiple-punch tissue microarray of 211 colorectal cancer resections. Membranous/cytoplasmic and nuclear expression was evaluated in tumour and buds. Tumour budding was assessed on corresponding whole tissue slides. Relationship to Ki-67 and caspase-3 was investigated. Analysis of Kirsten Ras (KRAS), proto-oncogene B-RAF (BRAF) and cytosine-phosphate-guanosine island methylator phenotype (CIMP) was performed. Membranous/cytoplasmic and nuclear TrkB were strongly, inversely correlated (P < 0.0001; r = -0.41). Membranous/cytoplasmic TrkB was overexpressed in buds compared to the main tumour body (P < 0.0001), associated with larger tumours (P = 0.0236), high-grade budding (P = 0.0011) and KRAS mutation (P = 0.0008). Nuclear TrkB was absent in buds (P <0.0001) and in high-grade budding cancers (P =0.0073). Among patients with membranous/cytoplasmic TrkB-positive buds, high tumour membranous/cytoplasmic TrkB expression was a significant, independent adverse prognostic factor [P = 0.033; 1.79, 95% confidence interval (CI) 1.05-3.05]. Inverse correlations between membranous/cytoplasmic TrkB and Ki-67 (r = -0.41; P < 0.0001) and caspase-3 (r =-0.19; P < 0.05) were observed. CONCLUSIONS: Membranous/cytoplasmic TrkB may promote an epithelial-mesenchymal transition (EMT)-like phenotype with high-grade budding and maintain viability of buds themselves.