Refining Risk Criteria May Substantially Reduce Unnecessary Additional Surgeries after Local Resection of T1 Colorectal Cancer.

BACKGROUND: The low positive predictive value for lymph node metastases (LNM) of common practice risk criteria (CPRC) in T1 colorectal carcinoma (CRC) leads to manyunnecessary additional surgeries following local resection. This study aimed to identify criteria that may improve on the CPRC. METHODS: Logistic regression analysis was performed to determine the association of diverse variables with LNM or 'poor outcome' (LNM and/or distant metastases and/or recurrence) in a single center T1 CRC cohort. The diagnostic capacity of the set of variables obtained was compared with that of the CPRC. RESULTS: The study comprised 161 cases. Poorly differentiated clusters (PDC) and tumor budding grade > 1 (TB > 1) were the only independent variables associated with LNM. The area under the curve (AUC) for these criteria was 0.808 (CI 95% 0.717-0.880) compared to 0.582 (CI 95% 0.479-0.680) for CPRC. TB > 1 and lymphovascular invasion (LVI) were independently associated with 'poor outcome', with an AUC of 0.801 (CI 95% 0.731-0.859), while the AUC for CPRC was 0.691 (CI 95% 0.603-0.752). TB > 1, combined either with PDC or LVI, would reduce false positives between 41.5% and 45% without significantly increasing false negatives. CONCLUSIONS: Indicating additional surgery in T1 CRC only when either TB > 1, PDC, or LVI are present could reduce unnecessary surgeries significantly.

Correlations of pathomorphological parameters between lesions at the invasive front and lymph node metastases in colorectal cancer: a retrospective clinical study.

BACKGROUND: Lymph node (LN) metastasis is one of the most important indicators to evaluate stage, choose treatment strategy, and predict outcome of colorectal cancer (CRC). The morphological correlation between primary tumors and LN metastases can help predict the incidence of LN metastasis in CRC more accurately and assist with more individualized risk-stratification management decisions. METHODS: A retrospective study was devised with paired tissue specimens from the invasive front of primary tumors and LN metastases in 426 patients after a radial surgery for CRC. According to the presence (N +) or absence (N-) of regional LN metastasis and the number of LN metastases (pN1a/1b/1c/2a/2b), comparisons were performed regarding tumor budding (TB) and poorly-differentiated clusters (PDC). In addition, their correlation with the incidence of LN metastasis and the extent were explored. RESULTS: The TB and PDC in the invasive front of primary tumors presented significant correlations with the incidence of LN metastasis and the number of LN metastases in CRC (P < 0.001). TB2/3 led to a risk of LN metastasis 6.68-fold higher than TB1, while PDC2/3 resulted in a risk of LN metastasis 8.46-fold higher than PDC1. Additionally, the risk of developing 4 or more LN metastases was 3.08-fold and 2.86-fold higher upon TB2/3 and PDC2/3 than that with TB1 and PDC1, respectively. Moderate positive correlations were found between the invasive front of primary tumors and LN metastases in terms of TB and PDC, respectively. CONCLUSIONS: TB and PDC, at the invasive tumor front are important morphological markers to evaluate LN metastasis in CRC, and they can be employed as reference indicators to assess or predict the potential of LN metastasis in CRC in clinical practice.

Colorectal Carcinomas: Searching for New Histological Parameters Associated with Lymph Node Metastases.

Background and Objectives: Colorectal cancer (CRC) continues to be an essential public health problem. Our study aimed to evaluate the prognostic significance of classic prognostic factors and some less-studied histopathological parameters in CRC. Materials and Methods: We performed a retrospective study on 71 colorectal carcinoma patients who underwent surgery at the "Pius Brînzeu" County Clinical Emergency Hospital in Timișoara, Romania. We analyzed the classic parameters but also tumor budding (TB), poorly differentiated clusters (PDCs) of cells, tumor-infiltrating lymphocytes (TILs), and the configuration of the tumor border on hematoxylin-eosin slides. Results: A high degree of malignancy (p = 0.006), deep invasion of the intestinal wall (p = 0.003), an advanced stage of the disease (p < 0.0001), lymphovascular invasion (p < 0.0001), perineural invasion (p < 0.0001), high-grade TB (p < 0.0001), high-grade PDCs (p < 0.0001), infiltrative tumor border configuration (p < 0.0001) showed a positive correlation with lymph node metastases. Conclusions: The analyzed parameters positively correlate with unfavorable prognostic factors in CRC. We highlight the value of classic prognostic factors along with a series of less-known parameters that are more accessible and easier to evaluate using standard staining techniques and that could predict the risk of relapse or aggressive evolution in patients with CRC.

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, Pavlic 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.

Intravoxel incoherent motion MRI for rectal cancer: correlation of diffusion and perfusion characteristics with clinical-pathologic factors.

BACKGROUND: Colorectal cancer is the most common cause of cancer-related death worldwide. Magnetic resonance imaging (MRI) has become a promising alternative method for staging the cancer. PURPOSE: To evaluate parameters of intravoxel incoherent motion (IVIM) and their relationships with clinical-pathologic factors in rectal cancers. MATERIAL AND METHODS: A total of 51 patients with histopathologically proven rectal cancer who underwent preoperative pelvic MRI were prospectively enrolled. Parameters (ADC, D, D*, and f) derived from IVIM-diffusion-weighted imaging (DWI) were independently measured by two radiologists. Student's t-test, receiver operating characteristic curves, and Spearman correlation were used for statistical analysis. RESULTS: ADC, D, and D* were significantly higher in pT1-2 tumors than in pT3-4 tumors (1.108 ± 0.233 vs. 0.950 ± 0.176, 0.796 ± 0.199 vs. 0.684 ± 0.114, 0.013 ± 0.005 vs. 0.008 ± 0.003, respectively; P < 0.05). D* exhibited a strong correlation with the tumor stage (r = -0.675, P < 0.001). In poorly differentiated cluster (PDC) grading, ADC, D*, and f were significantly lower in high-grade tumors than in low-grade tumors (0.905 ± 0.148 vs. 1.064 ± 0.200, 0.008 ± 0.002 vs. 0.011 ± 0.005, and 0.252 ± 0.032 vs. 0.348 ± 0.058, respectively; P < 0.05). The f value exhibited a significantly strong correlation with the PDC grades (r = -0.842, P < 0.001), and higher sensitivity and specificity (95.2% and 75.9%) than those shown by the ADC, D, and D* values. CONCLUSION: IVIM parameters, especially f, demonstrated a strong correlation with histologic grades and showed a better performance in differentiating between high- and low-grade rectal cancers. These parameters would be helpful in predicting tumor aggressiveness and prognosis.

Molecular subtypes of invasive breast carcinoma of no special type, their correlation with histopathological features, Ki 67 index and tumor budding: A retrospective comparative study.

Context: Tumor budding (TB), poorly differentiated clusters (PDCs), and Ki 67 index are proven adverse prognostic factors in breast carcinoma. Though the relation of Ki 67 index with molecular subtypes of breast carcinoma have been extensively studied, there is very limited information on the role of TB and PDCs. Aims: To grade TB, PDCs, and Ki 67 index and assess histological features and relationship of all these with molecular subtypes of invasive breast carcinoma of no special type. Methods and Material: Retrospective study of 148 cases from 1/1/2019 to 30/12/2019. Division of molecular groups - Luminal A, Luminal B, Her2 neu positive, and triple-negative breast carcinomas (TNBC), and Ki 67 index grades based on St Gallen criteria, intratumoral and peritumoral TB and PDC grades as per the International Tumor Budding Consensus Conference (ITBCC) criteria for colon and correlation between these and other histological features with the molecular subtypes were done. Statistical Analysis: Chi-square test, univariate and multivariate logistic regression models were used. Results: Significant correlation was seen between TB and lymphovascular emboli, Luminal B tumors with high-grade TB and PDCs, Her 2 neu positive and TNBC tumors with low-grade TB, circumscribed tumor margins, tumor necrosis, and Luminal B, Her 2 neu positive and TNBC tumors with larger tumor size and high nuclear grades. Conclusions: TB and PDCs are useful in the prognostication of Luminal A and B tumors when the Ki 67 index values are low/intermediate. Her 2 neu positive and TNBC tumors have a high nuclear grade with necrosis and no association with TB or PDCs.

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

Morphological features including infiltrative growth, tumour budding (TB), and poorly differentiated clusters (PDCs) have a firmly established negative predictive value in colorectal cancer (CRC). Despite extensive research, the mechanisms underlying different tumour growth patterns remain poorly understood. The aim of this study was to investigate the involvement of epithelial-mesenchymal transition (EMT) in TB and PDCs in CRC. Using laser-capture microdissection, we obtained distinct parts of the primary CRC including TB, PDCs, expansive tumour front, and the central part of the tumour, and analysed the expression of EMT-related markers, i.e. the miR-200 family, ZEB1/2, RND3, and CDH1. In TB, the miR-200 family and CDH1 were significantly downregulated, while ZEB2 was significantly upregulated. In PDCs, miR-141, miR-200c, and CDH1 were significantly downregulated. No significant differences were observed in the expression of any EMT-related markers between the expansive tumour front and the central part of the tumour. Our results suggest that both TB and PDCs are related to partial EMT. Discrete differences in morphology and expression of EMT-related markers between TB and PDCs indicate that they represent different manifestations of partial EMT. TB seems to be closer to complete EMT than PDCs. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

H3K27me3 Immunohistochemical Loss Predicts Lower Response to Neo-Adjuvant Chemo-Radiotherapy in Rectal Carcinoma.

A watch-and-wait approach was suggested to avoid the possible complications related to surgery in patients with rectal carcinoma showing clinical complete response after neoadjuvant chemo-radiotherapy (CRT). Since clinical response may not correlate with pathological response, markers with higher accuracy are needed to identify patients who are likely responders and could be spared surgery. This study aims to assess whether H3K27me3 immunohistochemical expression in pre-treatment rectal carcinoma predicts response to neoadjuvant CRT or shows prognostic relevance. We assessed H3K27me3 immunostaining in 46 endoscopic biopsies of rectal carcinomas treated with neoadjuvant CRT and surgery. H3K27me3 immunostaining was lost in 20, retained in 19, and inconclusive (absent in neoplastic and non-neoplastic cells) in 7 cases. Retained H3K27me3 immuno-expression was significantly associated with ypTNM stage 0 (p = 0.0111) and high tumor regression, measured using either five-tiered (p = 0.0042) or two-tiered Dworak tumor regression grade (p = 0.0009). Poor differentiation, determined counting the number of poorly differentiated clusters (PDC grade) or tumor budding (TB) foci (TB grade), in the pre-treatment biopsy, was significantly associated with a shorter time to progression after surgery (p = 0.008; p = 0.0093). However, only PDC grade (p = 0.0023), together with radial margin involvement (p = 0.0001), retained prognostic significance in the multivariate analysis. The assessment of H3K27me3 immunostaining in pre-treatment endoscopic biopsy of rectal carcinoma could be useful to predict response to neo-adjuvant CRT and to identify patients who could safely undergo watch-and-wait approach. PDC and TB grade in the pre-treatment biopsy could provide additional prognostic information in patients with rectal carcinoma treated with neoadjuvant CRT and surgery.

Cytoproliferative activity in colorectal poorly differentiated clusters: Biological significance in tumor setting.

BACKGROUND: Poorly differentiated clusters (PDCs) have gained a significant prognostic role in colorectal carcinomas (CRCs) being associated to high risk of lymph node metastasis, shorter survival time and poor prognosis. The knowledge in PDC biology is not completely clear. MATERIALS AND METHODS: We assessed Ki-67 LI in 45 CRCs showing ≥10 PDCs. We distinguished PDCs at the periphery of the tumor masses (pPDCs) from those within the tumor masses (cPDCs). We chose 3 cut-offs of Ki-67 labeling index (Ki-67 LI): <10%, 10-50%, and >50% of the labeled cells. RESULTS: Ki-67 LI in pPDCs was<10% in 37 cases (82%), 10-50% in 6 cases (13%) and >50%in 2 cases (5%); Ki-67 LI in cPDCs was<10% in 4 cases (23.5%), 10-50% in 4 (23.5%) and >50% in 9 (54%). Ki-67 LI in tumor budding foci (TBs) was <10% in 8 cases (32%), 10-50% in 8 (32%) and >50% in 9 (36%). The difference of Ki-67 LI reaches the statistical significance (p < 0.005). Ki-67 LI <10% in the pPDCs was associated with nodal metastases (pN+) (p < 0.0001), pTNM stage III and IV(p < 0.0001) and TB (p < 0.001). Ki-67 LI > 50% in cPDC was significantly associated withpT3-pT4 and advanced pTNM stages (p < 0.0001), N+ (p = 0.0001) and LVI (p < 0.05). CONCLUSION: Different Ki-67 LI detected between cPDCs and pPDCs suggesting a biological difference in PDCs. An actively proliferating central tumor areas can be distinguished from the peripheral portion of the tumors in which the cells interact with the stroma acquiring invasive and metastatic potential.

Development and initial validation of a deep learning algorithm to quantify histological features in colorectal carcinoma including tumour budding/poorly differentiated clusters.

AIMS: To develop and validate a deep learning algorithm to quantify a broad spectrum of histological features in colorectal carcinoma. METHODS AND RESULTS: A deep learning algorithm was trained on haematoxylin and eosin-stained slides from tissue microarrays of colorectal carcinomas (N = 230) to segment colorectal carcinoma digitised images into 13 regions and one object. The segmentation algorithm demonstrated moderate to almost perfect agreement with interpretations by gastrointestinal pathologists, and was applied to an independent test cohort of digitised whole slides of colorectal carcinoma (N = 136). The algorithm correctly classified mucinous and high-grade tumours, and identified significant differences between mismatch repair-proficient and mismatch repair-deficient (MMRD) tumours with regard to mucin, inflammatory stroma, and tumour-infiltrating lymphocytes (TILs). A cutoff of >44.4 TILs per mm2 carcinoma gave a sensitivity of 88% and a specificity of 73% in classifying MMRD carcinomas. Algorithm measures of tumour budding (TB) and poorly differentiated clusters (PDCs) outperformed TB grade derived from routine sign-out, and compared favourably with manual counts of TB/PDCs with regard to lymphatic, venous and perineural invasion. Comparable associations were seen between algorithm measures of TB/PDCs and manual counts of TB/PDCs for lymph node metastasis (all P < 0.001); however, stronger correlations were seen between the proportion of positive lymph nodes and algorithm measures of TB/PDCs. Stronger associations were also seen between distant metastasis and algorithm measures of TB/PDCs (P = 0.004) than between distant metastasis and TB (P = 0.04) and TB/PDC counts (P = 0.06). CONCLUSIONS: Our results highlight the potential of deep learning to identify and quantify a broad spectrum of histological features in colorectal carcinoma.

Clinical Significance of Preoperative Inflammatory Markers in Prediction of Prognosis in Node-Negative Colon Cancer: Correlation between Neutrophil-to-Lymphocyte Ratio and Poorly Differentiated Clusters.

Although stage I and II colon cancers (CC) generally show a very good prognosis, a small proportion of these patients dies from recurrent disease. The identification of high-risk patients, who may benefit from adjuvant chemotherapy, becomes therefore essential. We retrospectively evaluated 107 cases of stage I (n = 28, 26.2%) and II (n = 79, 73.8%) CC for correlations among preoperative inflammatory markers, histopathological factors and long-term prognosis. A neutrophil-to-lymphocyte ratio greater than 3 (H-NLR) and a platelet-to-lymphocyte ratio greater than 150 (H-PLR) were significantly associated with the presence of poorly differentiated clusters (PDC) (p = 0.007 and p = 0.039, respectively). In addition, H-NLR and PDC proved to be significant and independent survival prognosticators for overall survival (OS; p = 0.007 and p < 0.001, respectively), while PDC was the only significant prognostic factor for cancer-specific survival (CSS; p < 0.001,). Finally, the combination of H-NLR and PDC allowed an optimal stratification of OS and CSS in our cohort, suggesting a potential role in clinical practice for the identification of high-risk patients with stage I and II CC.

The presence of poorly differentiated clusters predicts survival in stage II colorectal cancer.

In stage II colorectal carcinoma (CRC), adjuvant chemotherapy is reserved to cases at high risk of adverse outcome. This study aims to investigate the prognostic value of tumor budding (TB) and poorly differentiated clusters (PDC) in this setting. In a cohort of 149 patients with surgically resected stage II CRC not undergoing neoadjuvant or adjuvant treatments, we assessed the prognostic value of several clinical-pathological variables, including PDC and TB, on cancer-specific survival (CSS). Rectal location, lymphovascular invasion, and a number of lymph nodes < 12 confirmed to be significant and independent predictors of shorter CSS. A total of 117 CRCs were graded as PDC-G1 (0-4 PDCs), 19 as PDC-G2 (5-9 PDCs), and 13 as PDC-G3 (> 9 PDCs). Ninety-eight cases had PDC absent. TB foci were found in 91 CRCs; 121 were classified Bd1, 16 were Bd2, and 12 were Bd3. PDC-G2/G3 was significantly prognostic of shorter CSS (P < 0.0001). Among PDC-G1 cases, the presence of PDC was significantly associated with reduced CSS (P < 0.0001). Moreover, in the whole 149 CRCs, it had higher sensitivity and specificity to identify high-risk patients, compared to PDC grade, and it was independently associated with shorter CSS at multivariate analysis. High TB grade (Bd3) was significantly associated with shorter CSS (P = 0.0001), but it lost prognostic value at multivariate analysis. These findings suggest that the presence of PDC in stage II CRCs might be added to the pool of high-risk factors, warranting the use of adjuvant chemotherapy.

Tumor Budding and Poorly Differentiated Clusters in Small Intestinal Adenocarcinoma.

The clinicopathologic and prognostic significances of tumor budding (TB) and poorly-differentiated clusters (PDC) have not been investigated in small intestinal adenocarcinomas (SIACs). In 236 surgically-resected SIACs, we counted TB (single cells or clusters ≤4 tumor cells) and PDC (clusters ≥5 tumor cells) at the peritumoral-invasive front (p) and in the intratumoral area (i) independently to classify as grade-1 (≤4), grade-2 (5-9), or grade-3 (≥10). Consequently, grades-2 and -3 were considered high-grade. High-pTB, -iTB, -pPDC, and -iPDC were observed in 174 (73.7%), 129 (54.7%), 118 (50.0%), and 85 (36.0%) cases, respectively. High-TB/PDCs were more frequently observed in tumors with high-grade, higher T- and N-categories and stage grouping, and perineural or lymphovascular invasion. Patients with high-TB/PDC had a shorter survival than those with low-TB/PDC. In a multivariate analysis, high-pTB, nonintestinal type, high N-category, retroperitoneal seeding, and microsatellite-stable were worse independent-prognostic predictors. Subgroup analysis demonstrated that patients with high-pTB showed worse survival (median: 42.5 months) than those with low-pTB (133.7 months; p = 0.007) in the lower stage (stages I-II) group. High-TB/PDC, both in peritumoral and intratumoral localizations, were associated with aggressive behaviors in SIACs. High-pTB can be used as an adverse prognostic indicator in SIAC patients, especially when patients are in early disease stages.

Poorly differentiated clusters in colorectal cancer: a current review and implications for future practice.

Poorly differentiated clusters (PDC), defined as small groups of ≥5 tumour cells without glandular differentiation, have gained recent attention as a promising prognostic factor in colorectal cancer (CRC). Numerous studies have shown PDC to be significantly associated with other adverse histopathological features and worse clinical outcomes. PDC may hold particular promise in stage II colon cancer, where risk stratification plays a critical role in patient selection for adjuvant chemotherapy. In addition, emerging evidence suggests that PDC can predict lymph node metastasis in endoscopically resected pT1 CRC, potentially helping the selection of patients for oncological resection. In 'head-to-head' comparisons, PDC grade has consistently outperformed conventional histological grading systems both in terms of risk stratification and reproducibility. With a number of large-scale studies now available, this review evaluates the evidence regarding the prognostic significance of PDC, considers its relationship with other emerging invasive front prognostic markers (such as tumour budding and stroma type), assesses its 'practice readiness', addressing issues such as interobserver reproducibility, scoring methodologies and special histological subtypes (e.g. micropapillary and mucinous carcinoma), and draws attention to ongoing challenges and areas in need of further study. Finally, emerging data on the role of PDC in non-colorectal cancers are briefly considered.

Clinicopathological significance of heterogeneic ezrin expression in poorly differentiated clusters of colorectal cancers.

Multicellular structures, such as tumor buddings and poorly differentiated clusters (PDC), exist at the invasive front of colorectal cancers (CRC). Although it has been reported that CRC with PDC showed frequent lymph node metastases with a worse prognosis, the molecular markers of PDC that are responsible for prognosis have not been identified. We here noticed for the first time that Ezrin, a regulator of the actin cytoskeleton, is expressed in the corner cells of PDC. We then aimed to verify whether heterogeneous Ezrin expression in PDC predicts the prognosis of CRC patients. We immunohistochemically analyzed Ezrin expression in PDC of 184 patients with completely resected stages I-III CRC. We established the Ezrin corner score (ECS), which quantifies the tendency of Ezrin-positive cells to accumulate at the corners of PDC. On the basis of ECS values, 2 indices, the mean ECS and the number of PDC with high ECS, were obtained. Both indices were significantly higher in CRC with lymphatic invasion, higher PDC grade, and presence of micropapillary (MP) PDC. The mean ECS-high group showed shorter recurrence-free survival than the mean ECS-low group but without significance. The other index, the number of ECS-high PDC, was significantly associated with recurrence-free survival. These results suggest that Ezrin is involved in PDC progression and lymphatic invasion, and that ECS may be a marker for aggressive PDC.

Poorly differentiated clusters (PDC) in colorectal cancer: Does their localization in tumor matter?

Poorly differentiated clusters (PDC) are aggregates of at least five neoplastic cells lacking evidence of glandular differentiation. By definition, they can be present at the invasive front (peripheral PDC or pPDC) and within the tumor stroma (central PDC or cPDC). In colorectal cancer (CRC), PDC are considered adverse prognosticators and seem to reflect epithelial mesenchymal transition (EMT). In this study, we have investigated the immuno-expression of two EMT-related proteins, E-cadherin and ß-catenin, in PDC of primary CRCs and matched liver metastases. pPDC always showed nuclear ß-catenin staining and diffusely reduced/absence of E-cadherin expression as opposed cPDC which showed nuclear ß-catenin immunoreactivity and E-cadherin expression in about 50% of cases. In addition, the pattern of ß-catenin and E-cadherin expression differed between PDC and the main tumor, and between primary CRC and liver metastasis (LM), in a percentage of cases. A discordant pattern of ß-catenin and E-cadherin expression between pPDC and cPDC, between main tumor and cPDC, and between primary CRC and LM, confirms that EMT is a dynamic and reversible process in CRC. On the overall, this suggests that pPDC and cPDC are biologically different. We may advocate that PDC develop at the tumor center (cPDC) and then some of them migrate towards the tumor periphery while progressively completing EMT process (pPDC). Based on these results, PDC presence and counting may have different prognostic relevance if the assessment is done at the invasive front of the tumor or in the intratumor stroma.

Poorly differentiated clusters: prognostic significance in colorectal carcinomas immunohistochemistry images.

Colorectal cancer (CRC) remains a major public health burden worldwide, despite increased knowledge on its pathogenesis and advances in therapy. We aimed to evaluate a new histological grading system based on poorly differentiated clusters (PDCs) counting - the PDCs grade (PDCs-G), and its clinicopathological and prognostic significance, compared to the World Health Organisation (WHO) grading system (WHO grade). We reviewed 71 surgical resection specimens for CRC from the Emergency County Hospital "Pius Brînzeu" Timisoara. The cases were graded using the WHO grade and the PDCs-G, with further analysis of their association with the other recognised prognostic parameters. Using the WHO grade, 9% of the analysed cases were G1, 80% G2, 11% G3, and none of the tumours was graded G4, while in the PDCs-G 16% were G1, 45% G2, and 39% G3. In multivariate analysis PDCs-G was significantly associated with the American Joint Committee on Cancer stage of the disease (AJCC stage) (p = 0.0003), depth of invasion (pT) (p = 0.0084), nodal status (LNM) (p < 0.0001), lymphovascular invasion (LVI) (p < 0.0001), perineural invasion (PNI) (p < 0.0052), and tumour border configuration (p < 0.0001). The novel grading system based on PDCs counting is an additional histological tool in the evaluation of CRC and a promising new prognostic factor for these patients.

Poorly Differentiated Clusters in Colorectal Adenocarcinomas Share Biological Similarities with Micropapillary Patterns as well as Tumor Buds.

In colorectal carcinoma, poorly differentiated clusters (PDCs) are a poor prognostic indicator and show morphological continuity and behavioral similarities to micropapillary patterns (MPPs) as well as tumor buds (TBs). Epithelial-mesenchymal transition (EMT) and inhibition of cancer-stromal interactions may contribute to the development of PDCs. To clarify the biological nature of PDCs, we examined immunohistochemical stainings for ß-catenin, Ki-67, E-cadherin, epithelial cell adhesion molecule (EpCAM), MUC1, and epithelial membrane antigen (EMA), which are associated with EMT and cancer-stromal interactions. The expression frequencies and patterns of PDCs, TBs, and differentiated neoplastic glands from the tumor center (TC) were compared. In the study group (117 cases), the nuclear ß-catenin staining index was higher in PDCs (37.3%) and TBs (43.3%) than in neoplastic glands from TC (8.9%, P < 0.001). The mean Ki-67 labeling index in TC was 71.5%, whereas it was decreased in PDCs (31.2%) and TBs (10.2%, P < 0.001). E-cadherin and EpCAM displayed a tendency to be found along the cell membrane in TC samples (91.5% and 92.3%, respectively), whereas they showed loss of membranous staining in PDC (44.4% and 36.8%, respectively) and TB samples (60.7% and 68.4%, respectively). An inside-out pattern for MUC1 and EMA was frequently observed in PDC (48.7% and 45.3%, respectively) and TB samples (46.2% and 45.3%, respectively), but not in TC samples. Our data demonstrate that there is a pathogenetic overlap among PDCs, TBs, and MPPs and suggest that they might represent sequential growth patterns that branch from common biological processes such as dedifferentiation and alteration in cancer-stromal interactions.

Prognostic significance of CDX2 immunoexpression in poorly differentiated clusters of colorectal carcinoma.

CDX2 is a transcription factor that acts as a tumor suppressor in colorectal cancer (CRC). Its loss triggers metastatic process and tumor progression; however, its prognostic role in patients with CRC is still controversial. Poorly differentiated clusters (PDCs) are aggregates of neoplastic cells which likely have high metastatic potential in CRC. In this study, we analyzed and compared CDX2 expression in PDC (CDX2-PDC) and corresponding main tumor (CDX2 main tumor) in 42 CRCs showing at least 10 PDC (PDC G3). Five of 42 CRCs (12%) were classified as CDX2 main tumor negative (4/5 were also PDC-CDX2 negative); all had tumor recurrence and died of CRC. Twenty nine of 42 cases were CDX2-PDC negative. Among CRC CDX2 main tumor positive, 15 had recurrences and 13 died from CRC; 13 and 11 of them, respectively, were CDX2-PDC negative. By assigning one point to CDX2 main tumor or CDX2-PDC positivity, we assessed CDX2-staining score for each case. Twelve cases had CDX2-staining score 2 (CDX2 positive in main tumor and PDC); 26 had score 1 (CDX2 positive in main tumor or PDC), and 4 had CDX2 score 0 (CDX2 negative in main tumor and PDC). In our patients, CDX2-staining score had higher prognostic value compared to CDX2 main tumor or CDX2-PDC alone. In addition, it represented a significant and independent prognostic variable for disease-free survival (DFS) and cancer-specific survival (CSS). Our findings suggest that, although loss of CDX2 in the main tumor identifies high-risk patients with high specificity, CDX2-PDC should also be considered in CDX2 main tumor positive cases to predict prognosis.

Histological grading based on poorly differentiated clusters is predictive of tumour response and clinical outcome in rectal carcinoma treated with neoadjuvant chemoradiotherapy.

AIMS: The clinical outcome of patients with locally advanced rectal cancer who undergo neoadjuvant chemoradiotherapy (CRT) is influenced by the tumour response to treatment, which is reflected by tumour regression grade and post-treatment (y) TNM stage. Little is known about the prognostic value of pretreatment histopathological features of the tumour that may be useful to discriminate potential non-responders and to design tailored therapeutic strategies. In this study, we aimed to investigate the prognostic role of poorly differentiated clusters (PDCs) of neoplastic cells in pretreatment biopsies of patients with rectal cancer treated with neoadjuvant CRT. METHODS AND RESULTS: Grading based on PDC counting was retrospectively applied to 204 pretreatment endoscopic biopsies of rectal carcinomas from patients treated with neoadjuvant CRT and surgery. Interobserver agreement in the assessment of PDC grade was good. High PDC grade was significantly associated with high yT stage (P = 0.044), yM+ status (P = 0.0004), and unchanged TNM stage or TNM upstaging (P = 0.032). In addition, high PDC grade was a significant and independent prognostic factor for cancer-specific survival. CONCLUSIONS: PDC grade may be assessed in preoperative biopsies of rectal cancer with good reproducibility. High PDC grade in a pretreatment tumour is significantly associated with a poor response to therapy. Hence, we suggest that PDC grading might be used as a significant predictive and prognostic factor in patients with locally advanced rectal cancer who are treated with neoadjuvant CRT, and to identify high-risk patients who need surgery and adjuvant chemotherapy.