Clinicopathological and Molecular Characteristics of Colorectal Signet Ring Cell Carcinoma: A Review

Emerging and under-recognised patterns of colorectal carcinoma morphologies: a comprehensive review

While the overwhelming majority of colorectal carcinomas (CRC) are diagnosed as adenocarcinoma not otherwise specified, there are numerous under-recognised morphologic patterns of CRC. These patterns are recognised by the WHO, appear in reporting manuals for the American Joint Committee of Cancer, and/or are listed on synoptic reports, while many other variants have either fallen out of favour or are emerging as future bona fide patterns. Herein, we discuss 13 variants: serrated adenocarcinoma, micropapillary adenocarcinoma, medullary carcinoma, neuroendocrine carcinoma, mucinous adenocarcinoma, signet-ring cell carcinoma, adenosquamous carcinoma, adenoma-like adenocarcinoma, lymphoglandular complex-like CRC, carcinoma with sarcomatoid components, cribriform-comedo-type adenocarcinoma, undifferentiated carcinoma and low-grade tubuloglandular adenocarcinoma. The purpose of this review is to scrutinise these variants by assessing their clinical characteristics, morphologic cues, as well as pitfalls, and address their prognostic significance. Our analysis aims to bring clarity and updated understanding to these variants, offering valuable insights for pathologists. This contributes to more nuanced CRC diagnosis and treatment strategies, highlighting the importance of recognising a broad spectrum of morphologic patterns in CRC.

The histological and molecular characteristics of early-onset colorectal cancer: a systematic review and meta-analysis

Background

Early-onset colorectal cancer (CRC), defined as diagnosis before age 50, has increased in recent decades. Although more often diagnosed at advanced stage, associations with other histological and molecular markers that impact prognosis and treatment remain to be clarified. We conducted a systematic review and meta-analysis concerning the prevalence of prognostic and predictive tumor markers for early- vs. late-onset CRC, including oncogene mutations, microsatellite instability (MSI), and emerging markers including immune cells and the consensus molecular subtypes.

Methods

We systematically searched PubMed for original research articles published between April 2013-January 2024. Included studies compared the prevalence of tumor markers in early- vs. late-onset CRC. A meta-analysis was completed and summary odds ratios (ORs) with 95% confidence intervals (CIs) were obtained from a random effects model via inverse variance weighting. A sensitivity analysis was completed to restrict the meta-analysis to studies that excluded individuals with Lynch syndrome, a hereditary condition that influences the distribution of tumor markers for early-onset CRC.

Results

In total, 149 articles were identified. Tumors from early-onset CRC are less likely to include mutations in KRAS (OR, 95% CI: 0.91, 0.85-0.98), BRAF (0.63, 0.51-0.78), APC (0.70, 0.58-0.84), and NRAS (0.88, 0.78-1.00) but more likely to include mutations in PTEN (1.68, 1.04-2.73) and TP53 (1.34, 1.24-1.45). After limiting to studies that excluded Lynch syndrome, the associations between early-onset CRC and BRAF (0.77, 0.64-0.92) and APC mutation (0.81, 0.67-0.97) were attenuated, while an inverse association with PIK3CA mutation was also observed (0.88, 0.78-0.99). Early-onset tumors are less likely to develop along the CpG Island Methylator Phenotype pathway (0.24, 0.10-0.57), but more likely to possess adverse histological features including high tumor grade (1.20, 1.15-1.25), and mucinous (1.22, 1.16-1.27) or signet ring histology (2.32, 2.08-2.57). A positive association with MSI status (1.31, 1.11-1.56) was also identified. Associations with immune markers and the consensus molecular subtypes are inconsistent.

Discussion

A lower prevalence of mutations in KRAS and BRAF is consistent with extended survival and superior response to targeted therapies for metastatic disease. Conversely, early-onset CRC is associated with aggressive histological subtypes and TP53 and PTEN mutations, which may serve as therapeutic targets.

A novel log odds of positive lymph nodes-based nomogram for predicting overall survival in patients with colorectal signet ring cell carcinoma: a SEER population-based study

PURPOSE

Considering the poor prognosis and high lymph node (LN) involvement rate of colorectal signet ring cell carcinoma (SRCC), this study aimed to construct a prognostic nomogram to predict overall survival (OS) with satisfactory accuracy and utility, based on LN status indicators with superior predictability.

METHODS

Using the Surveillance, Epidemiology, and End Results (SEER) database, we obtained cases of colorectal SRCC patients and employed univariate and multivariate Cox analyses to determine independent prognostic factors. Kaplan-Meier curves were utilized to visualize survival differences among these factors. Receiver operating characteristic curves were generated to assess predictive performances of models incorporating various LN status indicators. A novel nomogram, containing optimal LN status indicators and other prognostic factors, was developed to predict OS, whose discriminatory ability and accuracy were evaluated using calibration curves and decision curve analysis.

RESULTS

A total of 1663 SRCC patients were screened from SEER database. Older patients and those with grades III-IV, tumor sizes > 39 mm, T3/T4 stage, N1/N2 stage, M1 stage, and higher log odds of positive lymph nodes (LODDS) values exhibited poorer prognoses. Age, grade, tumor size, TNM stage, and LODDS were independent prognostic factors. The model containing N stage and LODDS outperformed the one relying solely on N stage as LN status indicator, resulting in a validated nomogram for accurately predicting OS in SRCC patients.

CONCLUSION

The integration of LODDS, N stage, and other risk factors into a nomogram offered precise OS predictions, enhancing therapeutic decision-making and tailored follow-up management for colorectal SRCC patients.

Prognostic implications of T stage in different pathological types of colorectal cancer: an observational study using SEER population-based data

OBJECTIVES

Colorectal cancer (CRC) encompasses a spectrum of pathological types, each exhibiting distinct biological behaviours that challenge the conventional T-staging system's predictive efficiency. Thus, this study aims to explore the prognostic significance of the T stage across various CRC pathological types, seeking to unravel insights that could enhance prognostic assessment in this complex disease.

STUDY DESIGN

We performed a retrospective analysis using the Surveillance, Epidemiology, and End Results (SEER) database for primary CRC cases from 2010 to 2017.

SETTING

The SEER database, comprising data from various US regional and state cancer registries, identified 39 321 patients with CRC. Our analysis focused on the three most common CRC pathological types: adenocarcinoma (AC), mucinous adenocarcinoma (MC) and signet ring cell carcinoma (SR).

PRIMARY OUTCOME MEASURES

The study used Cox regression models to evaluate how different pathological characteristics impact mortality risk in patients with CRC. Time-dependent receiver operating characteristic curves were also applied to assess the prognostic accuracy of various tumour node metastasis (TNM)/non-mucinous (NM) stages.

RESULTS

We observed significant associations between T stage and mortality risk for patients with AC and MC. Notably, in comparison to those at T1 stage, patients with AC in the T4 stage demonstrated a 2.01-fold increase in mortality risk (HR=2.01, 95% CI: 1.89 to 2.15), while patients with MC at T4 stage showed a 1.42-fold increase (HR=1.42, 95% CI: 1.03 to 1.97). However, within the SR group, T stages did not independently impact survival, showing no significant distinction (HR=1.07, 95% CI: 0.59 to 1.95). Intriguingly, the traditional TNM staging systems demonstrated limited discriminatory power in predicting prognosis for patients with SR when compared with the more innovative NM staging systems.

CONCLUSIONS

This study uncovers important insights about the prognostic significance of the T stage in different types of CRC, highlighting the need for personalised assessments based on specific histological subtypes.

Racial disparities in colorectal cancer clinicopathological and molecular tumor characteristics: a systematic review

PURPOSE

African Americans have the highest colorectal cancer (CRC) mortality of all racial groups in the USA, which may relate to differences in healthcare access or advanced stage at diagnosis. Recent evidence indicates that differences in tumor characteristics may also underlie disparities in mortality. To highlight recent findings and areas for investigation, we completed the first systematic review of racial disparities in CRC tumor prognostic markers, including clinicopathological markers, microsatellite instability (MSI), oncogene mutations, and novel markers, including cancer stem cells and immune markers.

METHODS

Relevant studies were identified via PubMed, limited to original research published within the last 10 years. Ninety-six articles were identified that compared the prevalence of mortality-related CRC tumor characteristics in African Americans (or other African ancestry populations) to White cases.

RESULTS

Tumors from African ancestry cases are approximately 10% more likely to contain mutations in KRAS, which confer elevated mortality and resistance to epidermal growth factor receptor inhibition. Conversely, African Americans have approximately 50% lower odds for BRAF-mutant tumors, which occur less frequently but have similar effects on mortality and therapeutic resistance. There is less consistent evidence supporting disparities in mutations for other oncogenes, including PIK3CA, TP53, APC, NRAS, HER2, and PTEN, although higher rates of PIK3CA mutations and lower prevalence of MSI status for African ancestry cases are supported by recent evidence. Although emerging evidence suggests that immune markers reflecting anti-tumor immunity in the tumor microenvironment may be lower for African American cases, there is insufficient evidence to evaluate disparities in other novel markers, cancer stem cells, microRNAs, and the consensus molecular subtypes.

CONCLUSION

Higher rates of KRAS-mutant tumors in in African Americans may contribute to disparities in CRC mortality. Additional work is required to understand whether emerging markers, including immune cells, underlie the elevated CRC mortality observed for African Americans.

Spatial Epidemiology of Signet-ring Cell Colorectal Cancer in India

Background

Signet-ring cell colorectal carcinoma (SRCC) is an extremely aggressive yet uncommon histologic subtype of colorectal cancer (CRC) with an unknown etiology. There is a stark difference in the prevalence of signet cancers between Western countries and the Indian subcontinent; however, India itself is a vast and diverse country with variable cancer incidence.

Objective

To study the spatial epidemiology of SRCC in India for identifying regions with high prevalence.

Methods

This retrospective study included all patients diagnosed with colorectal adenocarcinoma at Tata Memorial Hospital, the largest colorectal cancer referral unit in India, between January 2020 and December 2022. Geocoding based on the location of the residence was done to map the incidences. Comparisons were performed between the proportion of signet cell and non-signet colorectal cancers.

Results

A total of 4100 patients with colon or rectal adenocarcinomas were included, of which signet cell histology was found in 624 (15%) patients. SRCC accounted for the highest proportions of CRCs in the Central (19%) and Northern (19%) regions, and the lowest in the North-Eastern (10%) and Western (12%) regions of India (P < 0.001), with non-overlapping confidence intervals. Compared with patients with non-signet CRCs, those with SRCC more commonly had colon cancers (22% vs. 17%; P = 0.003) and belonged to a lower socioeconomic background (67% vs. 59%; P < 0.001).

Conclusions

This study found that SRCCs accounted for a significant proportion of CRC cases in India, but there was no substantial disparity in distribution across regions.

Molecular Biomarkers and Signaling Pathways of Cancer Stem Cells in Colorectal Cancer

Colorectal cancer (CRC) is the third most frequently found cancer in the world, and it is frequently discovered when it is already far along in its development. About 20% of cases of CRC are metastatic and incurable. There is more and more evidence that colorectal cancer stem cells (CCSCs), which are in charge of tumor growth, recurrence, and resistance to treatment, are what make CRC so different. Because we know more about stem cell biology, we quickly learned about the molecular processes and possible cross-talk between signaling pathways that affect the balance of cells in the gut and cancer. Wnt, Notch, TGF-β, and Hedgehog are examples of signaling pathway members whose genes may change to produce CCSCs. These genes control self-renewal and pluripotency in SCs and then decide the function and phenotype of CCSCs. However, in terms of their ability to create tumors and susceptibility to chemotherapeutic drugs, CSCs differ from normal stem cells and the bulk of tumor cells. This may be the reason for the higher rate of cancer recurrence in patients who underwent both surgery and chemotherapy treatment. Scientists have found that a group of uncontrolled miRNAs related to CCSCs affect stemness properties. These miRNAs control CCSC functions like changing the expression of cell cycle genes, metastasis, and drug resistance mechanisms. CCSC-related miRNAs mostly control signal pathways that are known to be important for CCSC biology. The biomarkers (CD markers and miRNA) for CCSCs and their diagnostic roles are the main topics of this review study.

Colon Cancer Cells Evade Drug Action by Enhancing Drug Metabolism

Colorectal cancer (CRC) is the second most deadly cancer worldwide. One key reason is the failure of therapies that target RAS proteins, which represent approximately 40% of CRC cases. Despite the recent discovery of multiple alternative signalling pathways that contribute to resistance, durable therapies remain an unmet need. Here, we use liquid chromatography/mass spectrometry (LC/MS) analyses on Drosophila CRC tumour models to identify multiple metabolites in the glucuronidation pathway-a toxin clearance pathway-as upregulated in trametinib-resistant RAS/APC/P53 ("RAP") tumours compared to trametinib-sensitive RASG12V tumours. Elevating glucuronidation was sufficient to direct trametinib resistance in RASG12V animals while, conversely, inhibiting different steps along the glucuronidation pathway strongly reversed RAP resistance to trametinib. For example, blocking an initial HDAC1-mediated deacetylation step with the FDA-approved drug vorinostat strongly suppressed trametinib resistance in Drosophila RAP tumours. We provide functional evidence that pairing oncogenic RAS with hyperactive WNT activity strongly elevates PI3K/AKT/GLUT signalling, which in turn directs elevated glucose and subsequent glucuronidation. Finally, we show that this mechanism of trametinib resistance is conserved in an KRAS/APC/TP53 mouse CRC tumour organoid model. Our observations demonstrate a key mechanism by which oncogenic RAS/WNT activity promotes increased drug clearance in CRC. The majority of targeted therapies are glucuronidated, and our results provide a specific path towards abrogating this resistance in clinical trials.

WNT Signalling Promotes NF-κB Activation and Drug Resistance in KRAS-Mutant Colorectal Cancer

Approximately 40% of colorectal cancer (CRC) cases are characterized by KRAS mutations, rendering them insensitive to most CRC therapies. While the reasons for this resistance remain incompletely understood, one key aspect is genetic complexity: in CRC, oncogenic KRAS is most commonly paired with mutations that alter WNT and P53 activities ("RAP"). Here, we demonstrate that elevated WNT activity upregulates canonical (NF-κB) signalling in both Drosophila and human RAS mutant tumours. This upregulation required Toll-1 and Toll-9 and resulted in reduced efficacy of RAS pathway targeted drugs such as the MEK inhibitor trametinib. Inhibiting WNT activity pharmacologically significantly suppressed trametinib resistance in RAP tumours and more genetically complex RAP-containing 'patient avatar' models. WNT/MEK drug inhibitor combinations were further improved by targeting brm, shg, ago, rhoGAPp190 and upf1, highlighting these genes as candidate biomarkers for patients sensitive to this duel approach. These findings shed light on how genetic complexity impacts drug resistance and proposes a therapeutic strategy to reverse this resistance.

The Travels of Signet-Ring Cell Carcinoma: From Colon to Stomach and Duodenum

Colorectal cancer (CRC) metastasizing to the stomach and duodenum is rare. Even rarer is when the CRC subtype is signet-ring cell carcinoma (SRCC). Endoscopic findings of CRC metastasis to the stomach have been described as solitary and submucosal while duodenal metastasis has been observed to be exophytic. In this report, we describe a case of a middle-aged man with colon SRCC presenting with oral intolerance. He was found to have concurrent metastases to the stomach and duodenum and died 8 months after his SRCC diagnosis.

Signet cell rectal carcinoma with prostatic involvement detected by FAPI-04 PET-MRI fusion

A 60-year-old male patient diagnosed with mucinous adenocarcinoma of lower third of rectum underwent abdominoperineal resection and permanent colostomy followed by adjuvant chemotherapy. Response evaluation with F-18 FDG PET-CT showed a complete metabolic response. After 6 months, CEA levels started increasing and clinically a recurrence was suspected. A restaging FDG PET-CT showed no obvious malignant disease. Patient presented again within a month with complaints of urinary retention and haematuria. CEA levels were further elevated, and Ga-68 FAPI-04 (FAPI) PET-CT was performed. FAPI PET-CT revealed prostatic and seminal vesicle disease involvement. Additionally, an MRI of pelvis was done and fused with FAPI PET for confirmation of prostatic involvement.

Comparison of survival outcomes and survival prediction in patients with primary colorectal MANEC and primary colorectal SRCC: a population-based propensity-score matching study

PURPOSE

Primary mixed adeno-neuroendocrine carcinoma (MANEC) and primary signet-ring cell cancer (SRCC) are two rare but highly malignant tumors in colorectal cancer. Therefore, we attempted to compare the tumors' survival outcomes, identify risk factors, and ultimately evaluate the prognosis by developing a nomogram.

METHODS

We identified 755 MANEC and 5836 SRCC patients of colorectal cancer. PSM was used to balance the influence of baseline clinical and pathological differences. Kaplan-Meier method was used to compare the prognosis of different pathological grades and AJCC stages. Cox proportional hazards model was used to identify potential prognostic factors for the two groups. Finally, we developed a nomogram and evaluated the feasibility of the model.

RESULTS

After PSM, the median OS and CSS of MANEC patients were significantly better than those of SRCC patients in stage III-IV (P < 0.001) but similar in stage I-II. The median OS and CSS of MANEC patients in each pathological grade were also greater than those of SRCC patients. Patients with MANEC and SRCC who underwent lymph node dissection in more than four areas had longer survival time. MANEC patients benefited from postoperative chemotherapy and radiotherapy; among SRCC patients, those who received preoperative and postoperative comprehensive chemotherapy and radiotherapy had benefits in OS and CSS.

CONCLUSION

Both MANEC and SRCC are often diagnosed in advanced stages, highlighting the importance of early screening. Despite the better prognosis of MANEC compared to SRCC, both types of patients require the formulation of personalized treatment strategies based on different risk factors combined with column charts.

Metastatic Signet Ring Cell Adenocarcinoma Manifesting as Chronic Leg Pain

Signet ring cell carcinoma, a type of gastrointestinal system-related cancer, rarely metastasizes to the skeletal muscle. We present signet ring-cell carcinoma in a 28-year-old man who presented with left lower extremity pain and swelling. Imaging showed thickening of the distal esophagus, intestines, and bladder wall. Endoscopy revealed friable gastric mucosa and stenosis in the ascending colon, but biopsies were unrevealing. Leg muscle biopsy showed metastatic adenocarcinoma with focal signet ring features. Carcinoembryonic antigen and cancer antigen 19-9 were elevated. A gastrointestinal primary tumor was suspected. Our case urges clinicians to consider this rare cancer in patients presenting with skeletal muscle mass.

Colorectal Signet Ring Cell Carcinoma Presenting as Ulcerating Rectosigmoid Stricture

Colorectal signet ring cell carcinoma is a rare type of colon cancer. Early diagnosis remains challenging because of nonspecific colonoscopy findings, such as diffuse circumferential thickening, stricture, and ulcerations, and the potential absence of typical pathological features in the initial biopsy sample. In this article, we report a 41-year-old man with ulcerating rectosigmoid stricture in the rectosigmoid colon with inconclusive histology. Subsequently, the patient developed small bowel obstruction and was diagnosed with stage 4 colorectal signet ring cell carcinoma with peritoneal carcinomatosis.

Histological transformation to signet-ring cell carcinoma in a patient with clinically aggressive poorly differentiated adenocarcinoma of the ascending colon after response to chemotherapy plus cetuximab: a case report

BACKGROUND

Alteration of chemosensitivity or tumor aggressiveness in response to chemotherapy has been reported, and liquid biopsy assessment during chemotherapy for colorectal cancers has confirmed the acquisition of mutations in various oncogenes. However, the occurrence of histological transformation seems to be extremely rare in colorectal cancers, and the few existing case reports of this transformation are from lung cancer and breast cancer. In this report, we describe the histological transformation of clinically aggressive scirrhous-type poorly differentiated adenocarcinoma of the ascending colon to signet-ring cell carcinoma in almost all recurrent tumors that were confirmed by autopsy after response to chemotherapy plus cetuximab.

CASE PRESENTATION

A 59-year-old woman visited our hospital with whole abdominal pain and body weight loss and was diagnosed with scirrhous-type poorly differentiated adenocarcinoma of the ascending colon with aggressive lymph node metastases. The intrinsic chemosensitivity of the tumors was evident upon initiation of mFOLFOX6 plus cetuximab therapy, and right hemicolectomy was performed, and the tumor obviously remained in the peripancreatic area, paraaortic region, or other retroperitoneal areas. The ascending colon tumors mainly consisted of poorly differentiated adenocarcinoma and were not associated with signet-ring cell components except for minute clusters in a few lymphatic emboli in the main tumor. Chemotherapy was continued, and metastases were eliminated at 8 months after the operation; this response was maintained for an additional 4 months. Discontinuation of chemotherapy plus cetuximab resulted in immediate tumor recurrence and rapid expansion, and the patient died of the recurrent tumor 1 year and 2 months after the operation. Autopsy specimens revealed that almost all of the recurrent tumors exhibited transformation and consisted of signet-ring cell histology.

CONCLUSION

This case might suggest that various oncogene mutations or epigenetic changes resulting from chemotherapy, especially regimens that include cetuximab, contribute to the transformation of non-signet-ring cell colorectal carcinoma to signet-ring cell carcinoma histology and can promote the aggressive clinical progression characteristic of signet-ring cell carcinoma.

Case Report: Intramural colonic signet ring cell carcinoma presenting as intestinal pseudo-obstruction: A case presentation and review of the literature

Colorectal cancer (CRC) is the third most common cancer in the world. Other than adenocarcinomas, exceptional tumors of the colon and rectum represent a neglected clinical issue due to their rarity. Signet ring cell carcinoma (SRCC) is a rare subtype of CRC and has an extremely poor prognosis due to its advanced stage at diagnosis. Here we report a rare case of colorectal SRCC manifested as recurrent intestinal obstruction with a negative colonoscopy. Finally, he was diagnosed with signet ring cell carcinoma of the colon by postoperative pathology. It emphasized the special feature of intramural tumor growth without penetrating the mucosa in SRCC, which requires timely surgical intervention to avoid delay in diagnosis and treatment.

The CCL27-CCR10 axis contributes to promoting proliferation, migration, and invasion of lung squamous cell carcinoma

Lung cancer is characterized by its high mortality and morbidity. A deep understanding of the molecular mechanisms of lung cancer tumorigenesis helps to develop novel lung cancer diagnostic and therapeutic strategies. However, the picture of the associated molecular landscape is not yet complete. As understood, chemokine-receptor interactions contribute much to lung cancer tumorigenesis, in which CCR10 also plays an important role. This study aimed to expand the knowledge of CCR10 in lung squamous cell carcinoma (LUSC) in the manner of molecular mechanism and biological functions. Using GEPIA database, the survival analysis between LUSC patients with high and low CCR10 expressions was performed, showing that CCR10 could be regarded as a risk factor for LUSC patients. Subsequently, CCR10 protein and mRNA expressions in LUSC were examined by qRT-PCR and western blot respectively. The results indicated that CCR10 was highly expressed in LUSC cells. The results of CCK-8, colony formation, and Transwell assays presented that CCL27, the ligand of CCR10, promoted proliferative, migratory, and invasive abilities of LUSC cells by activating CCR10. Also, the PI3K/AKT signaling pathway was verified as the involved pathway by western blot. Overall, it could be concluded that the CCL27-CCR10 regulatory axis can activate the PI3K/AKT pathway fostering the malignant features of LUSC cells.

PD-L1 testing by immunohistochemistry in immuno-oncology

Immunotherapy, based on immune checkpoint inhibitors targeting the Programmed cell death ligand 1 (PD-L1) and/or Programmed Death Receptor 1 (PD-1), has substantially improved the outcomes of patients with various cancers. However, only ~30% of patients benefit from immune checkpoint inhibitors. Tumor PD-L1 expression, assessed by immunohistochemistry, is the most widely validated and used predictive biomarker to guide the selection of patients for immune checkpoint inhibitors. PD-L1 assessment may be challenging due to the necessity for different companion diagnostic assays for required specific immune checkpoint inhibitors and a relatively high level of inter-assay variability in terms of performance and cutoff levels. In this review, we discuss the role of PD-L1 immunohistochemistry as a predictive test in immunotherapy (immuno-oncology), highlight the complexity of the PD-L1 testing landscape, discuss various preanalytical, analytical and clinical issues that are associated with PD-L1 assays, and provide some insights into optimization of PD-L1 as a predictive biomarker in immuno-oncology.

Case report: Preclinical efficacy of NEDD8 and proteasome inhibitors in patient-derived models of signet ring high-grade mucinous colorectal cancer from a Lynch syndrome patient

High-grade mucinous colorectal cancer (HGM CRC) is particularly aggressive, prone to metastasis and treatment resistance, frequently accompanied by "signet ring" cancer cells. A sizeable fraction of HGM CRCs (20-40%) arises in the context of the Lynch Syndrome, an autosomal hereditary syndrome that predisposes to microsatellite instable (MSI) CRC. Development of patient-derived preclinical models for this challenging subtype of colorectal cancer represents an unmet need in oncology. We describe here successful propagation of preclinical models from a case of early-onset, MSI-positive metastatic colorectal cancer in a male Lynch syndrome patient, refractory to standard care (FOLFOX6, FOLFIRI-Panitumumab) and, surprisingly, also to immunotherapy. Surgical material from a debulking operation was implanted in NOD/SCID mice, successfully yielding one patient-derived xenograft (PDX). PDX explants were subsequently used to generate 2D and 3D cell cultures. Histologically, all models resembled the tumor of origin, displaying a high-grade mucinous phenotype with signet ring cells. For preclinical exploration of alternative treatments, in light of recent findings, we considered inhibition of the proteasome by bortezomib and of the related NEDD8 pathway by pevonedistat. Indeed, sensitivity to bortezomib was observed in mucinous adenocarcinoma of the lung, and we previously found that HGM CRC is preferentially sensitive to pevonedistat in models with low or absent expression of cadherin 17 (CDH17), a differentiation marker. We therefore performed IHC on the tumor and models, and observed no CDH17 expression, suggesting sensitivity to pevonedistat. Both bortezomib and pevonedistat showed strong activity on 2D cells at 72 hours and on 3D organoids at 7 days, thus providing valid options for in vivo testing. Accordingly, three PDX cohorts were treated for four weeks, respectively with vehicle, bortezomib and pevonedistat. Both drugs significantly reduced tumor growth, as compared to the vehicle group. Interestingly, while bortezomib was more effective in vitro, pevonedistat was more effective in vivo. Drug efficacy was further substantiated by a reduction of cellularity and of Ki67-positive cells in the treated tumors. These results highlight proteasome and NEDD8 inhibition as potentially effective therapeutic approaches against Lynch syndrome-associated HGM CRC, also when the disease is refractory to all available treatment options.

Can a Solitary Juvenile Polyp Be Regarded as a Nonmalignant Polyp?

Juvenile polyps (JPs) are common, developing mostly as solitary, hamartomatous lesions in the colorectum, and principally affect pediatric patients. Solitary JPs are recognized as benign, with a negligible malignant transformation rate. Primary signet ring cell carcinoma is a rare type of colorectal cancer (0.1%-2.6%) that presents mostly at an advanced stage in younger patients and affects the right-sided colon, with extensive lymphatic invasion and peritoneal dissemination, resulting in a poorer prognosis compared with conventional colorectal cancer. We report a rare case of signet ring cell carcinoma in a solitary JP treated with endoscopic mucosal resection.

Predictors of Long-Time Survivors in Nonmetastatic Colorectal Signet Ring Cell Carcinoma: A Large Population-Based Study

Background

Colorectal signet ring cell carcinoma (SRCC) is a rare and distinct subtype of colorectal cancer (CRC), with extremely poor prognosis and aggressive tumor biological behavior. In this study, we aimed to analyze the clinicopathological characteristics and to identify the independent predictors of long-time survivors (LTSs) of nonmetastatic colorectal SRCC.

Methods

Patients diagnosed with nonmetastatic colorectal SRCC were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. We compared and analyzed the clinicopathological characteristics between LTSs (patients survived over 5 years) and non-LTSs (patients survived of or less than 5 years). Afterwards, multivariate logistic regression analysis was used to identify independent predictors of LTSs, which were further used to construct a nomogram model to predict the probability of being LTSs.

Results

We enrolled 2050 patients with nonmetastatic colorectal SRCC, consisting of 1441 non-LTSs and 609 LTSs. Multivariate logistic regression analysis revealed that race, marital status, tumor infiltration, lymph node involvement, and primary tumor treatment were independent predictors of LTSs. In addition, these five parameters were incorporated into a nomogram model to predict the probability of being LTSs. In terms of the model performance, the calibration curve revealed good agreement between observed and predicted probability of LTSs, and receiving operator characteristic curve showed acceptable discriminative capacity in the training and validation cohorts.

Conclusion

Collectively, we analyzed and profiled the clinicopathological characteristics of LTSs in patients with nonmetastatic colorectal SRCC. Race, marital status, T stage, N stage, and primary tumor treatment were independent predictors of LTSs.

Analysis of immune related gene expression profiles and immune cell components in patients with Barrett esophagus

Barrett's esophagus (BE) is a well-known precancerous condition of esophageal adenocarcinoma. However, the immune cells and immune related genes involved in BE development and progression are not fully understood. Therefore, our study attempted to investigate the roles of immune cells and immune related genes in BE patients. The raw gene expression data were downloaded from the GEO database. The limma package in R was used to screen differentially expressed genes (DEGs). Then we performed the least absolute shrinkage and selection operator (LASSO) and random forest (RF) analyses to screen key genes. The proportion of infiltrated immune cells was evaluated using the CIBERSORT algorithm between BE and normal esophagus (NE) samples. The spearman index was used to show the correlations of immune genes and immune cells. Receiver operating characteristic (ROC) curves were used to assess the diagnostic value of key genes in BE. A total of 103 differentially expressed immune-related genes were identified between BE samples and normal samples. Then, 7 genes (CD1A, LTF, FABP4, PGC, TCF7L2, INSR,SEMA3C) were obtained after Lasso analysis and RF modeling. CIBERSORT analysis revealed that resting CD4 T memory cells and gamma delta T cells were present at significantly lower levels in BE samples. Moreover, plasma cell and regulatory T cells were present at significantly higher levels in BE samples than in NE samples. INSR had the highest AUC values in ROC analysis. We identified 7 immune related genes and 4 different immune cells in our study, that may play vital roles in the occurrence and development of BE. Our findings improve the understanding of the molecular mechanisms of BE.

A Signet Cell Carcinoma of the Ileum: A Rare Differential Diagnosis of Intestinal Pathology with Fistula Mimicking Crohn's Disease

Colorectal cancer (CRC) is the third most common cancer and the fourth most common cause of cancer-related death in the USA. Primary signet ring cell carcinoma (SRCC) of the colon and rectum is extremely rare with a reported incidence of less than 1%. Here we present the case of a 41-year-old man who presented with abdominal pain, severe microcytic anaemia and a negative faecal occult blood test (FOBT). A CT scan of the abdomen revealed thickening of the terminal ileum and proximal right colon with extensive lymphadenopathy and a fistula tract extending from the terminal ileum to the right buttock. Endoscopic features like cobblestoning of the ileocolic junction along with elevated blood and stool inflammatory markers raised suspicion of Crohn’s disease (CD). However, histopathological study surprisingly revealed primary colorectal signet cell carcinoma (PCRSCC) with no evidence of CD. Cases of simultaneous PCRSCC and CD have been reported, but no clear association has been established. Our case is unique in that it presented with classic clinical features of CD, but PCRSCC without any histological evidence of underlying CD was found on histology.

A Rare Case of Signet Ring Cell Colon Cancer Presenting as Adult Colorectal Intussusception

Signet ring cell carcinoma of the rectum is rare and typically presents with advanced disease. We report a case of a 68-year-old man who presented with left lower quadrant pain and was found to have signet ring cell carcinoma with intussusception. This case is unusual because of its polypoid growth pattern and apparent early pathological stage. We discuss the differential diagnoses and prognosis.

Clinical significance of signet ring cells in surgical esophageal and esophagogastric junction adenocarcinoma: A systematic review and meta-analysis

BACKGROUND

The clinical significance of signet ring cells (SRCs) in surgical esophageal and esophagogastric junction adenocarcinoma (EEGJA) remains unclear now.

AIM

To explore the association between the presence of SRCs and the clinicopathological and prognostic characteristics in surgical EEGJA patients by combining and analyzing relevant studies.

METHODS

The PubMed, Web of Science, and EMBASE electronic databases were searched for the relevant literature up to March 28, 2021. The relative risk (RR) with 95% confidence interval (CI) was calculated to assess the relationship between SRCs and clinicopathological parameters of surgical EEGJA patients, and the hazard ratio (HR) with 95%CI was calculated to explore the impact of SRC on the prognosis. All statistical analyses were conducted with STATA 12.0 software.

RESULTS

A total of ten articles were included, involving 30322 EEGJA patients. The pooled results indicated that the presence of SRCs was significantly associated with tumor location (RR: 0.76, 95%CI: 0.61-0.96, P = 0.022; I² = 49.4%, P = 0.160) and tumor-node-metastasis stage (RR: 1.30, 95%CI: 1.02-1.65, P = 0.031; I² = 73.1%, P = 0.002). Meanwhile, the presence of SRCs in surgical EEGJA patients predicted a poor overall survival (HR: 1.36, 95%CI: 1.12-1.65, P = 0.002; I² = 85.7%, P < 0.001) and disease-specific survival (HR: 1.86, 95%CI: 1.55-2.25, P < 0.001; I² = 63.1%, P = 0.043).

CONCLUSION

The presence of SRCs is related with advanced tumor stage and poor prognosis and could serve as a reliable and effective parameter for the prediction of postoperative survival and formulation of therapy strategy in EEGJA patients. However, more high-quality studies are still needed to verify the above findings.