Tumour budding and poorly differentiated clusters in colon cancer - different manifestations of partial epithelial-mesenchymal transition

The association between histopathological growth patterns with tumor budding and poorly differentiated clusters in colorectal liver metastasis treated with preoperative systemic therapy

The liver's unique cellular structure makes it a frequent site for metastatic cancer. In colorectal liver metastasis (CRLM), surgical resection is essential for long-term survival. Histopathological growth patterns (HGPs) in CRLM, including desmoplastic and nondesmoplastic patterns, provide critical prognostic information. Tumor budding (TB) and poorly differentiated clusters (PDCs), indicators of aggressive cancer behavior, are evaluated using standardized histological scoring systems and are linked to epithelial-mesenchymal transition. This study explored the correlation between HGPs, TB, and PDCs in CRLM. Archived data from Thammasat University Hospital, including resected CRLM specimens, were analyzed. This study evaluated 51 CRLM resection specimens treated with preoperative systemic therapy, finding most to be nondesmoplastic with low TB and grade 1 PDC. Desmoplastic growth was significantly more prevalent in cases receiving preoperative chemotherapy than those that did not. Higher 3-year mortality was noted in nondesmoplastic groups and those with higher TB and tumor regression grade (TRG) scores. Significant correlations were observed between HGPs, TB, and PDCs, despite challenges in assessing these parameters due to issues with noncancer cells, extracellular mucin, bile ductular proliferation, and retraction artifacts. This study underscores the prognostic significance of HGPs, TB, PDCs, and TRG scores in CRLM, highlighting the need for precise histopathological evaluation for more accurate prognostic implications.

Evaluation of tumor budding with virtual panCK stains generated by novel multi-model CNN framework

As the global incidence of cancer continues to rise rapidly, the need for swift and precise diagnoses has become increasingly pressing. Pathologists commonly rely on H&E-panCK stain pairs for various aspects of cancer diagnosis, including the detection of occult tumor cells and the evaluation of tumor budding. Nevertheless, conventional chemical staining methods suffer from notable drawbacks, such as time-intensive processes and irreversible staining outcomes. The virtual stain technique, leveraging generative adversarial network (GAN), has emerged as a promising alternative to chemical stains. This approach aims to transform biopsy scans (often H&E) into other stain types. Despite achieving notable progress in recent years, current state-of-the-art virtual staining models confront challenges that hinder their efficacy, particularly in achieving accurate staining outcomes under specific conditions. These limitations have impeded the practical integration of virtual staining into diagnostic practices. To address the goal of producing virtual panCK stains capable of replacing chemical panCK, we propose an innovative multi-model framework. Our approach involves employing a combination of Mask-RCNN (for cell segmentation) and GAN models to extract cytokeratin distribution from chemical H&E images. Additionally, we introduce a tailored dynamic GAN model to convert H&E images into virtual panCK stains, integrating the derived cytokeratin distribution. Our framework is motivated by the fact that the unique pattern of the panCK is derived from cytokeratin distribution. As a proof of concept, we employ our virtual panCK stains to evaluate tumor budding in 45 H&E whole-slide images taken from breast cancer-invaded lymph nodes . Through thorough validation by both pathologists and the QuPath software, our virtual panCK stains demonstrate a remarkable level of accuracy. In stark contrast, the accuracy of state-of-the-art single cycleGAN virtual panCK stains is negligible. To our best knowledge, this is the first instance of a multi-model virtual panCK framework and the utilization of virtual panCK for tumor budding assessment. Our framework excels in generating dependable virtual panCK stains with significantly improved efficiency, thereby considerably reducing turnaround times in diagnosis. Furthermore, its outcomes are easily comprehensible even to pathologists who may not be well-versed in computer technology. We firmly believe that our framework has the potential to advance the field of virtual stain, thereby making significant strides towards improved cancer diagnosis.

Preoperative Noninvasive Evaluation of Tumor Budding in Rectal Cancer Using Multiparameter MRI Radiomics

RATIONALE AND OBJECTIVES

To assess the value of a multiparametric magnetic resonance imaging (MRI)-based model integrating radiomics features with clinical and MRI semantic features for preoperative evaluation of tumor budding (TB) in rectal cancer.

MATERIALS AND METHODS

A total of 120 patients with pathologically confirmed rectal cancer were retrospectively analyzed. The patients were randomized into training and validation cohorts in a 6:4 ratio. Radiomics features were extracted and selected from preoperative T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and contrast-enhanced T1-weighted imaging (T1CE) sequences, after which the corresponding radiomics score (RS) was calculated, and the radiomics models (T2WI model, DWI model, and T1CE model) were constructed. Logistic regression analysis was selected to develop a combined model integrated RST2WI, RSDWI, RST1CE, and clinical and MRI semantic features. The efficacy of each model in diagnosing TB grade was observed by the receiver operating characteristic (ROC) curve. Decision curve analysis (DCA) was used to assess the clinical benefits of the models.

RESULTS

Seven features were extracted and selected from each T2WI, DWI, and T1CE sequence to calculate the corresponding RS and construct the corresponding radiomics model. MRI reported N stage was an independent risk factor for TB. The area under the ROC curve of the combined model was 0.961 and 0.891 in the training and validation cohorts, respectively. The combined model showed better performance than the other models. DCA showed that the net benefit of the combined model was better than that of the other models in the vast majority of threshold probabilities.

CONCLUSION

A combined model integrating radiomics features and MRI semantic features allows for noninvasive preoperative evaluation of TB grading in patients with rectal cancer.

High KRT17 expression in tumour budding indicates immunologically 'hot' tumour budding and predicts good survival in patients with colorectal cancer

Objectives

Emerging evidence has demonstrated that tumour budding (TB) is negatively associated with T-lymphocyte infiltration in CRC. Despite extensive research, the molecular characteristics of immunologically 'hot' TB remain poorly understood.

Methods

We quantified the number of TB by haematoxylin-eosin (H&E) sections and the densities of CD3+ and CD8+ T-lymphocytes by immunohistochemistry in a CRC cohort of 351 cases who underwent curative resection. We analysed the differential expression and T-lymphocyte infiltration score of 37 human epithelial keratins in CRC using RNA sequencing from the TCGA dataset. In 278 TB-positive cases, KRT17 expression was evaluated in tumour centre (TC) and TB with a staining score. Patient demographic, clinicopathological features and survival rates were analysed.

Results

In a CRC cohort of 351 cases, low-grade TB was associated with high CD3+ and CD8+ T-cell densities in the invasive margin (IM) but not in the TC. Of 37 human epithelial keratins, only KRT17 expression in TB had an apparent association with TB-grade and T-lymphocyte infiltration. In 278 TB-positive cases, high KRT17 expression in TB (KRT17TB) was negatively associated with low-grade TB and positively associated with high CD3+ and CD8+ T-cell densities in IM. High KRT17TB predicted early tumour grade, absence of lymph node metastasis and absence of tumour deposits. Additionally, patients with high KRT17TB had good overall survival and disease-free survival. Notably, low KRT17TB can specifically identify those patients with a poor prognosis among colorectal cancer patients with low TB and high T-lymphocyte infiltration.

Conclusions

KRT17 can be employed as a new indicator for distinguishing different immunological TBs.

Intratumoral Budding and CD8-Positive T-cell Density in Pretreatment Biopsies as a Predictor of Response to Neoadjuvant Chemoradiotherapy in Advanced Rectal Cancer

BACKGROUND

Neoadjuvant chemoradiotherapy (CRT) is the standard treatment for advanced rectal cancer. Yet, the response to CRT varies from complete response to zero tumor regression.

MATERIALS AND METHODS

The impact of intratumoral budding (ITB) and intratumoral CD8+ cell density on response to CRT and survival were evaluated in biopsy samples from 266 patients with advanced rectal cancer who were treated with long-course neoadjuvant CRT. The expression of epithelial-mesenchymal transition (EMT) markers was compared between patients with high and low ITB, using data from 174 patients with RNA sequencing.

RESULTS

High ITB was observed in 62 patients (23.3%). There was no association between ITB and CD8+ cell density. The multivariable logistic regression analysis showed that high CD8+ cell density (OR, 2.69; 95% CI, 1.45-4.98; P = .002) was associated with good response to CRT, whereas high ITB (OR, 0.33; 95% CI, 0.14-0.80; P = .014) was associated with poor response. Multivariable Cox regression analysis for survival showed that high CD8+ cell density was associated with better recurrence-free survival (HR, 0.41; 95% CI, 0.24-0.72; P = .002) and overall survival (HR, 0.36; 95% CI, 0.17-0.74; P = .005), but significance values for ITB were marginal (P = .104 for recurrence-free survival and P = .163 for overall survival). The expression of EMT-related genes was not significantly different between patients with high and low ITB.

CONCLUSION

ITB and CD8+ cell density in biopsy samples may serve as useful biomarkers to predict therapy response in patients with rectal cancer treated with neoadjuvant CRT.

Tight Junction Claudins and Occludin Are Differentially Regulated and Expressed in Genomically Defined Subsets of Colon Cancer

Metastatic colon cancer remains incurable despite improvements in survival outcomes. New therapies based on the discovery of colon cancer genomic subsets could improve outcomes. Colon cancers from genomic studies with publicly available data were examined to define the expression and regulation of the major tight junction proteins claudins and occludin in genomic groups. Putative regulations of the promoters of tight junction genes by colon-cancer-deregulated pathways were evaluated in silico. The effect of claudin mRNA expression levels on survival of colon cancer patients was examined. Common mutations in colon-cancer-related genes showed variable prevalence in genomically identified groups. Claudin genes were rarely mutated in colon cancer patients. Genomically identified groups of colon cancer displayed distinct regulation of claudins and occludin at the mRNA level. Claudin gene promoters possessed clustered sites of binding sequences for transcription factors TCF4 and SMADs, consistent with a key regulatory role of the WNT and TGFβ pathways in their expression. Although an effect of claudin mRNA expression on survival of colon cancer patients as a whole was not prominent, survival of genomic subsets was significantly influenced by claudin mRNA expression. mRNA expression of the main tight junction genes showed differential regulation in various genomically defined subgroups of colon cancer. These data pinpoint a distinct role of claudins and pathways that regulate them in these subgroups and suggest that subgroups of colon cancer should be considered in future efforts to therapeutically target claudins.

Buds, clusters, and transitions in 21st century colorectal carcinoma: revolution or reinvention?†

Tumour budding (TB) describes single or small groups of neoplastic cells that lack continuity with an advancing tumour front. Poorly differentiated clusters (PDCs) are larger and qualitatively different. TB grade and PDCs may predict a worse outcome in colorectal carcinoma and other cancers and fall into the category of 'invasive front prognostic markers' that also includes intratumoural stroma type. Epithelial-mesenchymal transition (EMT) allows the adoption by epithelial cells of mesenchymal characteristics such as dyscohesion, migration, and stromal invasion. TB and PDCs harbor alterations in EMT-related proteins and RNAs and may be morphological manifestations of EMT. However, persistence of epithelioid features and absence of a full complement of typical alterations in TB and PDCs may indicate 'partial EMT', i.e. an intermediate/hybrid state. Recently, Pavlič et al asserted that TB and PDCs in colorectal cancer represent different manifestations of partial EMT and, perhaps controversially, that TB is closer than PDCs to complete transition. In clinical practice, low inter-observer agreement for invasive front prognostic markers is a potential problem. The UK colorectal cancer pathology dataset advises assessment of TB and recommends the use of an international consensus system, but time will tell if we are adopting reliable prognostic markers or reinventing the wheel. Additional studies of TB, PDCs, and EMT will presumably allow greater insight into their role in tumour development and progression. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Analyzing the invasive front of colorectal cancer - By punching tissue block or laser capture microdissection?

The aim of this study was to determine the advantages and limitations of two commonly used sampling techniques, i.e., punching tissue block (PTB) and laser capture microdissection (LCM) when investigating tumor cell-derived gene expression patterns at the invasive front of colorectal cancer (CRC). We obtained samples from 20 surgically removed CRCs at locations crucial for tumor progression, i.e., the central part, the expansive front and the infiltrative front exhibiting tumor budding (TB), using both sampling techniques. At each location, we separately analyzed the expressions of miR-200 family (miR-141, miR-200a, miR-200b, miR-200c and miR-429), known as reliable markers of epithelial-mesenchymal transition (EMT). We found significant downregulation of all members of miR-200 family at the infiltrative front in comparison to the central part regardless of the used sampling technique. However, when comparing miR-200 expression between the expansive and the infiltrative front, we found significant downregulation of all tested miR-200 at the infiltrative front only in samples obtained by LCM. Our results suggest that, PTB is an adequate technique for studying the differences in tumor gene expression between the central part and the invasive front of CRC, but is insufficient to analyze and compare morphologically distinct patterns along the invasive front including TB. For this purpose, the use of LCM is essential.

Interactions between circRNAs and miR-141 in Cancer: From Pathogenesis to Diagnosis and Therapy

The function of non-coding RNAs (ncRNAs) in the pathogenesis and development of cancer is indisputable. Molecular mechanisms underlying carcinogenesis involve the aberrant expression of ncRNAs, including circular RNAs (circRNAs), and microRNAs (miRNAs). CircRNAs are a class of single-stranded, covalently closed RNAs responsible for maintaining cellular homeostasis through their diverse functions. As a part of the competing endogenous RNA (ceRNAs) network, they play a central role in the regulation of accessibility of miRNAs to their mRNA targets. The interplay between these molecular players is based on the primary role of circRNAs that act as miRNAs sponges, and the circRNA/miRNA imbalance plays a central role in different pathologies including cancer. Herein, we present the latest state of knowledge about interactions between circRNAs and miR-141, a well-known member of the miR-200 family, in malignant transformation, with emphasis on the biological role of circRNA/miR-141/mRNA networks as a future target for novel anti-cancer therapies.

Tumor budding as a potential prognostic marker in determining the behavior of primary liver cancers

Hepatocellular (HCC) and intrahepatic cholangiocarcinoma (ICC), the most common primary tumors of the liver, are among the most important causes of cancer deaths worldwide. Because patients with primary liver tumors are frequently diagnosed at an advanced stage and have high mortality, many efforts have been made to identify new markers to determine their behavior and treatment, similar to those in other solid organ tumors. Recently, morphological assessment of tumor budding (TB) has been revealed as a promising prognostic finding to predict tumor behavior and survival across several different tumor types. Currently, the TB score in colorectal cancer has been revealed as an important parameter in pathology report protocols to determine the course of the disease. Regarding the liver, despite enormous data showing that many mechanisms involved in TB are associated with tumor behavior in both HCC and ICC, studies focusing on the role of TB in predicting the behavior and prognosis of these tumors have started to be investigated very recently. The purpose of this review is to present data about TB in primary tumors of the liver, pointing out the potential role of this parameter in determining the course of the disease, and emphasize the need to increase the number of further studies focusing on the evaluation of this parameter with an overview of the mechanisms involved in TB.