The molecular background of mucinous carcinoma beyond MUC2

Extent of Resection and Long-Term Outcomes for Appendiceal Adenocarcinoma: a SEER Database Analysis of Mucinous and non-Mucinous Histologies

BACKGROUND

Mucinous appendiceal adenocarcinomas (MAA) and non-mucinous appendiceal adenocarcinomas (NMAA) demonstrate differences in rates and patterns of recurrence, which may inform the appropriate extent of surgical resection (i.e., appendectomy versus colectomy). The impact of extent of resection on disease-specific survival (DSS) for each histologic subtype was assessed.

PATIENTS AND METHODS

Patients with resected, non-metastatic MAA and NMAA were identified in the Surveillance, Epidemiology, and End Results database (2000-2020). Multivariable models were created to examine predictors of colectomy for each histologic subtype. DSS was calculated using Kaplan-Meier estimates and examined using Cox proportional hazards modeling.

RESULTS

Among 4674 patients (MAA: n = 1990, 42.6%; NMAA: n = 2684, 57.4%), the majority (67.8%) underwent colectomy. Among colectomy patients, the rate of nodal positivity increased with higher T-stage (MAA: T1: 4.6%, T2: 4.0%, T3: 17.1%, T4: 21.6%, p < 0.001; NMAA: T1: 6.8%, T2: 11.4%, T3: 25.6%, T4: 43.8%, p < 0.001) and higher tumor grade (MAA: well differentiated: 7.7%, moderately differentiated: 19.2%, and poorly differentiated: 31.3%; NMAA: well differentiated: 9.0%, moderately differentiated: 20.5%, and 44.4%; p < 0.001). Nodal positivity was more frequently observed in NMAA (27.6% versus 16.4%, p < 0.001). Utilization of colectomy was associated with improved DSS for NMAA patients with T2 (log rank p = 0.095) and T3 (log rank p = 0.018) tumors as well as moderately differentiated histology (log rank p = 0.006). Utilization of colectomy was not associated with improved DSS for MAA patients, which was confirmed in a multivariable model for T-stage, grade, and use of adjuvant chemotherapy [hazard ratio (HR) 1.00, 95% confidence interval (CI) 0.81-1.22].

CONCLUSIONS

Colectomy was associated with improved DSS for patients with NMAA but not MAA. Colectomy for MAA may not be required.

Primary mucinous adenocarcinoma of the urethra: A clinicopathological analysis of 35 cases

AIM

Primary mucinous adenocarcinoma of the urethra represents an extremely rare entity. We sought to characterise further these tumours' clinicopathological, immunohistochemical and molecular features.

METHODS AND RESULTS

Thirty-five cases were identified, occurring in 18 males and 17 females. The mean age at diagnosis was 65 years (28-89 years). The main presentation symptoms were haematuria and urinary outlet obstruction. Microscopic analysis revealed that all 35 tumours have stromal dissection by mucin. Ten tumours showed villoglandular dysplasia, nine showed mucinous metaplasia, two showed adenocarcinoma in situ and four showed signet ring cell features. All tumours were immunopositive for CEA, while immunonegative for nuclear β-catenin; 19 of 23 (83%) expressed high molecular weight cytokeratin; 19 of 33 (58%) CK7; 28 of 34 (82%) CK20; 32 of 35 (91%) CDX2; 22 of 27 (81%) cadherin-17 (CDH-17); 26 of 29 (90%) SATB2; and one of 31 (3%) GATA3. Mismatch repair gene products, including MLH1, PMS2, MSH2 and MSH6, were immunopositive, suggesting the MSI-low genotype of mucinous adenocarcinoma of the urethra. BRAF V600E and ALK rearrangements were not detected. During the mean follow-up of 20 months, nine patients either developed distant metastasis or succumbed to the illness.

CONCLUSION

Our study, encompassing the most extensive series of 35 cases of primary mucinous adenocarcinoma of the urethra, provides crucial insights into its precise diagnosis, management and potential targeted treatments. We found a greater CDX2, SATB2 and CDH17 sensitivity in these urethral tumours for the first time, to our knowledge. We identified characteristics such as an MSI-low profile, non-V600E BRAF mutations and an absence of ALK rearrangements.

POFUT1 and PLAGL2 are characteristic markers of mucinous colorectal cancer associated with MUC2 expression

Colorectal mucinous adenocarcinoma (MAC) is one of the most lethal histological types of colorectal cancer, and its mechanism of development is not well understood. In this study, we aimed to clarify the molecular characteristics of MAC via in silico analysis using The Cancer Genome Atlas database. The expression of genes on chromosome 20q (Chr20q) was negatively associated with the expression of MUC2, which is a key molecule that can be used to distinguish between MAC and nonmucinous adenocarcinoma (NMAC). This was consistent with a significant difference in copy number alteration of Chr20q between the two histological types. We further identified 475 differentially expressed genes (DEGs) between MAC and NMAC, and some of the Chr20q genes among the DEGs are considered to be pivotal genes used to define MAC. Both in vitro and in vivo analysis showed that simultaneous knockdown of POFUT1 and PLAGL2, both of which are located on Chr20q, promoted MUC2 expression. Moreover, these genes were highly expressed in NMAC but not in MAC according to the results of immunohistological studies using human samples. In conclusion, POFUT1 and PLAGL2 are considered to be important for defining MAC, and these genes are associated with MUC2 expression.

Histologic and genomic characterization of a primary mucinous carcinoma of the skin

Aims

Primary skin mucinous carcinoma is a rare sweat gland neoplasm with a high local recurrence rate after conventional excision but a low distant-metastasis rate. The genetic underpinning of skin mucinous carcinoma is presently unknown. Here, we sought to define whether the repertoire of somatic mutations of a primary mucinous carcinoma of the skin would be similar to that of mucinous breast carcinomas, given the histologic similarities between these tumor types.

Methods and results

The tumor was situated in the dermis and partially involved the subcutaneous fat. Tumor cells were suspended in periodic acid-Schiff diastaseresistant- positive mucin lakes and expressed cytokeratin 7, synaptophysin and estrogen receptor. DNA samples extracted from microdissected tumor and matched normal tissue were subjected to massively parallel sequencing targeting 410 cancer-related genes. The skin mucinous tumor was found to have a low tumor mutation burden, but to harbor a clonal GATA3 frameshift mutation (p. T418Hfs*89) and amplification of FOXA1, genes not uncommonly altered in breast mucinous carcinomas.

Conclusions

In this primary skin mucinous carcinoma, GATA3 and FOXA1 driver genetic events were identified, consistent with a possible developmental relationship between skin and breast mucinous neoplasms.

Perianal Mucinous Adenocarcinoma Found Incidentally From Perianal Mass

Anal mucinous adenocarcinomas are very rare and usually arise from anal fistulas. We report a case of a 73-year-old man with a past medical history of hypertension admitted to our facility for evaluation of bleeding from a large, tender, left gluteal perianal mass. The patient reported the mass had been growing for over six years. On examination, an ulcerated, fungating large exophytic lesion was found extending from the anal verge laterally engulfing the left gluteus. The patient was anemic with low hemoglobin and hematocrit, as well as an elevated carcinoembryonic antigen level. A colonoscopy was performed during which an internal opening of a left-sided anal fistula was identified. The mass was biopsied and returned positive for a mucinous adenocarcinoma. Staging imaging including a computed tomography scan of the chest abdomen and pelvis did not show any metastatic disease. A magnetic resonance image of the pelvis revealed a locally invasive, heterogeneous tumor extending from the perianal soft tissue to the posterior wall of the anal canal and lower rectum. The patient was discussed at the interdisciplinary tumor board and completed five weeks of concurrent chemotherapy and radiation with 5-fluorouracil and a total of 28 fractions of radiation. He then underwent abdominoperineal resection with a vertical rectus abdominis myocutaneous flap. The patient was placed in the surgical intensive care unit and subsequently discharged in stable condition on postoperative day 14. This case highlights the presentation, diagnosis, and management of anal mucinous adenocarcinoma.

Pictilisib-Induced Resistance Is Mediated through FOXO1-Dependent Activation of Receptor Tyrosine Kinases in Mucinous Colorectal Adenocarcinoma Cells

The phosphatidylinositol (PI3K)/AKT/mTOR axis represents an important therapeutic target to treat human cancers. A well-described downstream target of the PI3K pathway is the forkhead box O (FOXO) transcription factor family. FOXOs have been implicated in many cellular responses, including drug-induced resistance in cancer cells. However, FOXO-dependent acute phase resistance mediated by pictilisib, a potent small molecule PI3K inhibitor (PI3Ki), has not been studied. Here, we report that pictilisib-induced adaptive resistance is regulated by the FOXO-dependent rebound activity of receptor tyrosine kinases (RTKs) in mucinous colorectal adenocarcinoma (MCA) cells. The resistance mediated by PI3K inhibition involves the nuclear localization of FOXO and the altered expression of RTKs, including ErbB2, ErbB3, EphA7, EphA10, IR, and IGF-R1 in MCA cells. Further, in the presence of FOXO siRNA, the pictilisib-induced feedback activation of RTK regulators (pERK and pAKT) was altered in MCA cells. Interestingly, the combinational treatment of pictilisib (Pi3Ki) and FOXO1i (AS1842856) synergistically reduced MCA cell viability and increased apoptosis. These results demonstrate that pictilisib used as a single agent induces acute resistance, partly through FOXO1 inhibition. Therefore, overcoming PI3Ki single-agent adaptive resistance by rational design of FOXO1 and PI3K inhibitor combinations could significantly enhance the therapeutic efficacy of PI3K-targeting drugs in MCA cells.

FAP promotes metastasis and chemoresistance via regulating YAP1 and macrophages in mucinous colorectal adenocarcinoma

Mucinous colorectal adenocarcinoma (MC) is less likely to respond to chemotherapy and is associated with poorer prognosis compared with non-MC (NMC). Fibroblast activation protein (FAP) was found and validated to be upregulated in MC patients and was negatively correlated with prognosis and therapeutic outcomes in colorectal cancer (CRC) patients who were treated with adjuvant chemotherapy. Overexpression of FAP promoted CRC cell growth, invasion and metastasis, and enhanced chemoresistance. Myosin phosphatase Rho-interacting protein (MPRIP) was identified as a direct interacting protein of FAP. FAP may influence the efficiency of chemotherapy and prognosis by promoting the crucial functions of CRC and inducing tumor-associated macrophages (TAMs) recruitment and M2 polarization through regulating theRas Homolog Family Member/Hippo/Yes-associated protein (Rho/Hippo/YAP) signaling pathway. Knockdown of FAP could reverse tumorigenicity and chemoresistance in CRC cells. Thus, FAP may serve as a marker for prognosis and therapeutic outcome, as well as a potential therapeutic target to overcome chemoresistance in MC patients.

Predictive value of intratumoral-metabolic heterogeneity derived from 18F-FDG PET/CT in distinguishing microsatellite instability status of colorectal carcinoma

Purpose/background

Microsatellite instability (MSI) status is a significant biomarker for the response to immune checkpoint inhibitors, response to 5-fluorouracil-based adjuvant chemotherapy, and prognosis in colorectal carcinoma (CRC). This study investigated the predictive value of intratumoral-metabolic heterogeneity (IMH) and conventional metabolic parameters derived from 18F-FDG PET/CT for MSI in patients with stage I-III CRC.

Methods

This study was a retrospective analysis of 152 CRC patients with pathologically proven MSI who underwent 18F-FDG PET/CT examination from January 2016 to May 2022. Intratumoral-metabolic heterogeneity (including heterogeneity index [HI] and heterogeneity factor [HF]) and conventional metabolic parameters (standardized uptake value [SUV], metabolic tumor volume [MTV], and total lesion glycolysis [TLG]) of the primary lesions were determined. MTV and SUVmean were calculated on the basis of the percentage threshold of SUVs at 30%-70%. TLG, HI, and HF were obtained on the basis of the above corresponding thresholds. MSI was determined by immunohistochemical evaluation. Differences in clinicopathologic and various metabolic parameters between MSI-High (MSI-H) and microsatellite stability (MSS) groups were assessed. Potential risk factors for MSI were assessed by logistic regression analyses and used for construction of the mathematical model. Area under the curve (AUC) were used to evaluate the predictive ability of factors for MSI.

Results

This study included 88 patients with CRC in stages I-III, including 19 (21.6%) patients with MSI-H and 69 (78.4%) patients with MSS. Poor differentiation, mucinous component, and various metabolic parameters including MTV30%, MTV40%, MTV50%, and MTV60%, as well as HI50%, HI60%, HI70%, and HF in the MSI-H group were significantly higher than those in the MSS group (all P < 0.05). In multivariate logistic regression analyses, post-standardized HI60% by Z-score (P = 0.037, OR: 2.107) and mucinous component (P < 0.001, OR:11.394) were independently correlated with MSI. AUC of HI60% and our model of the HI60% + mucinous component was 0.685 and 0.850, respectively (P = 0.019), and the AUC of HI30% in predicting the mucinous component was 0.663.

Conclusions

Intratumoral-metabolic heterogeneity derived from 18F-FDG PET/CT was higher in MSI-H CRC and predicted MSI in stage I-III CRC patients preoperatively. HI60% and mucinous component were independent risk factors for MSI. These findings provide new methods to predict the MSI and mucinous component for patients with CRC.

Molecular characterization of colorectal mucinous adenocarcinoma and adenocarcinoma, not otherwise specified, identified by multiomic data analysis

Adenocarcinoma not otherwise specified (AC) and mucinous adenocarcinoma (MC) have different biological behaviors and clinical features. We utilized our previous proteomic data and public transcriptome, single-cell transcriptome, and spatial transcriptome databases to profile the molecular atlas of the tumor microenvironments of MC, AC, and normal colon tissues. By exploring the general and specific molecular features of AC and MC, we found that AC was immune-active but exposed to a hypoxic microenvironment. MC cells could protect against DNA damage, and the microenvironment was unfavorable to leukocyte transendothelial migration. We identified several potential molecular and cellular targets of AC and MC for future research. We also highlighted that the major difference between AC and MC was not the variety of cell types and functions but possibly cell interactions. Stromal and epithelial cell interactions play important roles in both MC and AC, but different regulatory pathways were involved.

The Gut Microbiome, Microsatellite Status and the Response to Immunotherapy in Colorectal Cancer

There is increasing evidence in a range of cancer types that the microbiome plays a direct role in modulating the anti-cancer immune response both at the gut level and systemically. Differences in the gut microbiota have been shown to correlate with differences in immunotherapy responses in a range of non-gastrointestinal tract cancers. DNA mismatch repair-deficient (dMMR) colorectal cancer (CRC) is radically different to DNA mismatch repair-proficient (pMMR) CRC in clinical phenotype and in its very good responses to immunotherapy. While this has usually been thought to be due to the high mutational burden in dMMR CRC, the gut microbiome is radically different in dMMR and pMMR CRC in terms of both composition and diversity. It is probable that differences in the gut microbiota contribute to the varied responses to immunotherapy in dMMR versus pMMR CRC. Targeting the microbiome offers a way to boost the response and increase the selection of patients who might benefit from this therapy. This paper reviews the available literature on the role of the microbiome in the response to immunotherapy in dMMR and pMMR CRC, explores the potential causal relationship and discusses future directions for study in this exciting and rapidly changing field.

Single-cell profiling reveals differences between human classical adenocarcinoma and mucinous adenocarcinoma

Colorectal cancer is a highly heterogeneous disease. Most colorectal cancers are classical adenocarcinoma, and mucinous adenocarcinoma is a unique histological subtype that is known to respond poorly to chemoradiotherapy. The difference in prognosis between mucinous adenocarcinoma and classical adenocarcinoma is controversial. Here, to gain insight into the differences between classical adenocarcinoma and mucinous adenocarcinoma, we analyse 7 surgical tumour samples from 4 classical adenocarcinoma and 3 mucinous adenocarcinoma patients by single-cell RNA sequencing. Our results indicate that mucinous adenocarcinoma cancer cells have goblet cell-like properties, and express high levels of goblet cell markers (REG4, SPINK4, FCGBP and MUC2) compared to classical adenocarcinoma cancer cells. TFF3 is essential for the transcriptional regulation of these molecules, and may cooperate with RPS4X to eventually lead to the mucinous adenocarcinoma mucus phenotype. The observed molecular characteristics may be critical in the specific biological behavior of mucinous adenocarcinoma.

Prognosis of mucinous colon cancer is determined by histological biomarkers rather than microsatellite instability

The prognostic value of microsatellite instability (MSI), as well as other histological characteristics such as lymphovascular invasion (LI), perineural invasion (PNI) and extramural vascular invasion (EMVI), is unclear in colorectal mucinous carcinoma (MC). This study aims to determine the relevance of these factors in MC patients and analyses the role of MSI in stage III MC patients treated with adjuvant chemotherapy. A cohort of 650 patients diagnosed with stages I-IV colonic MC from 2000 to 2010 was selected from PALGA, the nationwide Dutch pathology databank. Histopathology was revised and mismatch repair (MMR) status determined. Univariate and multivariate survival analyses were performed. Deficient MMR (dMMR) was found in 33% of MCs and correlated with female gender and right-sidedness, but also with lower tumour stage (stages I/II: 73.2 versus 47%; P < 0.0001) and the absence of EMVI (9.7 versus 23.7%; P < 0.0001) and PNI (5.6 versus 12.7%; P = 0.005). On univariate analysis OS was better for dMMR MC than for proficient MMR (pMMR) MC (median OS of 9.7 versus 5.0 years; P = 0.009), but MMR status was no longer a relevant prognostic factor on multivariate analysis [hazard ratio (HR) = 0.91, 95% confidence interval (CI) = 0.70-1.18]. Stage III MC patients benefited from adjuvant chemotherapy, and dMMR status was associated with better OS in this group (HR = 0.35, 95% CI = 0.13-0.94). EMVI, LI and PNI, but not MMR, status are independent prognostic factors for survival in MC patients. Stage III MC patients benefit from adjuvant chemotherapy and dMMR status is associated with improved survival when adjuvant chemotherapy is given.

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.

Mucinous carcinoma of the breast: distinctive histopathologic and genetic characteristics

Mucinous carcinoma is a rare histologic type of breast cancer that, when classified with favorable histology, can be treated with different therapeutic options. This study reviews the histologic findings of mucinous carcinoma that support or exclude favorable histology and emphasizes the necessity of an appropriate gross examination with radiologic findings for an accurate diagnosis. In addition, unusual findings such as micropapillary arrangements and lobular differentiation in mucinous carcinoma and their implications for prognosis and treatment are reviewed. Mucinous carcinoma involves upregulation of MUC2, a mucus-associated gene common in mucinous carcinoma of the breast as well as various other organs. In mucinous carcinoma, the fraction of genome altered and tumor mutation burden are lower than those of invasive carcinoma of no special type, the most common histology of breast cancer. In addition, the genetic alterations found in mucinous carcinoma are diverse, unlike the pathognomonic genetic alterations observed in other histologic types of breast cancer. These genetic features support the importance of conventional microscopic evaluations for the pathologic differential diagnosis of mucinous carcinoma of the breast in routine practice. A variety of breast lesions, including mucinous cystadenocarcinoma and mucocele-like lesions, as well as mucinous carcinoma from other organs, can mimic mucinous carcinoma of the breast. In order to obtain an accurate pathologic diagnosis, careful evaluation of the overall histopathologic characteristics and ancillary testing are required to provide information on appropriate treatment and prognosis.

Femoral head metastases from primary mucinous lung adenocarcinoma with left hip pain: A case report and literature review

Background

Primary mucinous lung adenocarcinoma, a subtype of lung adenocarcinoma, is extremely rare. Currently, as there are no specific diagnostic features, it is easy to delay the diagnosis or even to misdiagnose when atypical symptoms are present.

Case summary

This case details a patient with primary mucinous lung adenocarcinoma and metastasis to the femoral head. The sole symptom was left hip pain and the initial diagnosis was isolated femoral head necrosis.

Conclusions

By presenting this rare case report and the experiences learned from it, we hope to assist clinicians to identify bone metastasis cases with non-typical symptoms in order to make the correct diagnosis as soon as possible.

NICD3 regulates the expression of MUC5AC and MUC2 by recruiting SMARCA4 and is involved in the differentiation of mucinous colorectal adenocarcinoma

Adenocarcinoma is the most prevalent histological subtype of colorectal cancer (CRC), with mucinous colorectal adenocarcinoma (MCA) being a unique form. Although the mucinous subtype is known to elicit a worse response to chemotherapy and immunotherapy than the nonmucinous subtype, its pathogenesis remains poorly understood. Neurogenic locus notch homolog protein 3 (NOTCH3), a member of the NOTCH subfamilies, is highly expressed in CRC. In the past three decades, many studies have been performed evaluating the biological role of NOTCH3 in CRC. However, the precise activities of NOTCH3 in MCA, as well as the mechanisms involved in its transcriptional control, are yet to be elucidated. Our finding showed that the critical transcriptional regulatory factor transcription activator BRG1 (SMARCA4) directly binds to the intracellular domain of NOTCH3 to control transcriptional regulation. Moreover, RNA‐sequencing results indicated a common targeting effect on the transcriptional activity of mucin‐5AC (MUC5AC) and mucin‐2 (MUC2) in CRC cells by NOTCH3 and SMARCA4. Furthermore, NOTCH3 was found to control the expressions of MUC5AC and MUC2 in a SMARCA4‐dependent manner. MUC5AC and MUC2, which encode two secreted mucins, are located on chromosome 11p15.5, and are linked to the development of MCA. This finding suggests that the interaction between NOTCH3 and SMARCA4 may be involved in MCA differentiation by jointly targeting MUC5AC and MUC2. Patients with MCA are often treated in accordance with CRC guidelines. Determining the relationship between NOTCH3 and SMARCA4 by demonstrating their interactions in the pathophysiology of MCA could provide novel therapeutic targets and help identify potential prognostic markers for MCA.

Mucinous histology is associated with poor prognosis in locally advanced colorectal adenocarcinoma treated with postoperative first-line adjuvant chemotherapy: A systematic review and meta-analysis

PURPOSE

Postoperative adjuvant chemotherapy followed surgery is the standard management for localized advanced colorectal carcinoma (CRC). Mucinous adenocarcinoma (MAC) is a peculiar histological subtype of CRC, but the prognosis of MAC patients is controversial. The objective of this study is to assess the implication of MAC in survival of patients treated with surgery and firs-line adjuvant chemotherapy.

METHODS

Studies describing outcomes for advanced MAC and non-specific adenocarcinoma (AC) of CRC patients treated with first-line postoperative adjuvant chemotherapy followed surgery were searched in PubMed, Embase, Medline, EBSCO, Wiley, and Cochrane Library (January 1963-August 2021). Hazard ratios (HRs) of overall survival (OS), disease-free survival (DFS) and cancer-specific survival (CSS) for MAC to AC were extracted. Random-effects model was used for calculating the pooled HRs and 95% confidence interval (CI).

RESULTS

This meta-analysis is comprised of 8 studies involving a total of 124,303 CRC patients treated with first-line adjuvant chemotherapy followed surgery. The pooled HR for MAC was 1.23 (95% CI, 1.07-1.41, p < 0.01, I² = 80%), and the DFS (HR, 2.95, 95% CI, 1.22-7.14) of MAC patients were significantly poorer than AC patients. Similar results were also observed in stage III and FOLFOX regimen subgroups.

CONCLUSION

MAC was a risk factor for prognosis of localized advanced CRC patients treated with postoperative first-line adjuvant chemotherapy. Thus, the role of first-line adjuvant chemotherapy regimens should be further studied in these MAC patients.

Combined Estrogen Alpha and Beta Receptor Expression Has a Prognostic Significance for Colorectal Cancer Patients

We reported that high estrogen receptor beta (ERβ) expression is independently associated with better prognosis in female colorectal cancer (CRC) patients. However, estrogen receptor alpha (ERα) is expressed at very low levels in normal colon mucosa, and its prognostic role in CRC has not been explored. Herein, we investigated the combined role of ERα and ERβ expression in the prognosis of female patients with CRC, which, to the best of our knowledge, is the first study to investigate this topic. A total number of 306 primary CRCs were immunostained for ERα and ERβ expression. A Cox regression model was used to evaluate overall survival (OS) and disease-free survival (DFS). The combined expression of high ERβ + negative ERα correlates with longer OS (HR = 0.23; 95% CI: 0.11–0.45, P &lt;0.0001) and DFS (HR = 0.10; 95% CI: 0.03–0.26, P &lt; 0.0001) and a more favorable tumor outcome, as well as significantly higher expression of antitumorigenic proteins than combined expression of low ERβ + positive ERα. Importantly, we found that low ERβ expression was associated with local recurrence of CRC, whereas ERα expression was correlated with liver metastasis. Overall, our results show that the combined high ERβ + negative ERα expression correlated with a better prognosis for CRC patients. Our results suggest that the combined expression of ERα and ERβ could be used as a predictive combination marker for CRC patients, especially for predicting DFS.

Prognostic Impact of An Integrative Landscape of Clinical, Immune, and Molecular Features in Non-Metastatic Rectal Cancer

Rectal Cancer (RC) is a complex disease that involves highly variable treatment responses. Currently, there is a lack of reliable markers beyond TNM to deliver a personalized treatment in a cancer setting where the goal is a curative treatment. Here, we performed an integrated characterization of the predictive and prognostic role of clinical features, mismatch-repair deficiency markers, HER2, CDX2, PD-L1 expression, and CD3-CD8+ tumor-infiltrating lymphocytes (TILs) coupled with targeted DNA sequencing of 76 non-metastatic RC patients assigned to total mesorectal excision upfront (TME; n = 15) or neoadjuvant chemo-radiotherapy treatment (nCRT; n = 61) followed by TME. Eighty-two percent of RC cases displayed mutations affecting cancer driver genes such as TP53, APC, KRAS, ATM, and PIK3CA. Good response to nCRT treatment was observed in approximately 40% of the RC cases, and poor pathological tumor regression was significantly associated with worse disease-free survival (DFS, HR = 3.45; 95%CI = 1.14-10.4; p = 0.028). High neutrophils-platelets score (NPS) (OR = 10.52; 95%CI=1.34-82.6; p = 0.025) and KRAS mutated cases (OR = 5.49; 95%CI = 1.06-28.4; p = 0.042) were identified as independent predictive factors of poor response to nCRT treatment in a multivariate analysis. Furthermore, a Cox proportional-hazard model showed that the KRAS mutational status was an independent prognostic factor associated with higher risk of local recurrence (HR = 9.68; 95%CI = 1.01-93.2; p <0.05) and shorter DFS (HR = 2.55; 95%CI = 1.05-6.21; p <0.05), while high CEA serum levels were associated with poor DFS (HR = 2.63; 95%CI = 1.01-6.85; p <0.05). Integrated clinical and molecular-based unsupervised analysis allowed us to identify two RC prognostic groups (cluster 1 and cluster 2) associated with disease-specific OS (HR = 20.64; 95%CI = 2.63-162.2; p <0.0001), metastasis-free survival (HR = 3.67; 95%CI = 1.22-11; p = 0.012), local recurrence-free survival (HR = 3.34; 95%CI = 0.96-11.6; p = 0.043) and worse DFS (HR = 2.68; 95%CI = 1.18-6.06; p = 0.012). The worst prognosis cluster 2 was enriched by stage III high-risk clinical tumors, poor responders to nCRT, with low TILs density and high frequency of KRAS and TP53 mutated cases compared with the best prognosis cluster 1 (p <0.05). Overall, this study provides a comprehensive and integrated characterization of non-metastatic RC cases as a new insight to deliver a personalized therapeutic approach.

Clinical Features, Molecular Alterations and Prognosis of Colorectal Adenocarcinoma With Mucinous Component in Chinese Patients

Mucinous adenocarcinoma (MAC) is conventionally diagnosed by WHO definition when the extracellular mucin is >50% of the tumor area, while tumors with <50% mucin are designated as having a mucinous component. The study is aimed at analyzing the clinicopathologic characteristics, mutation spectrum, and prognosis of colorectal adenocarcinoma with mucinous component (CAWMC). Mutation analyses for exon 2 to 4 of KRAS gene and exon 15 of BRAF gene were performed by Sanger sequencing. Expression of DNA mismatch repairs and P53 proteins were evaluated by immunohistochemistry. Density of tumor-infiltrating lymphocyte (TIL) status was scored. We also evaluated the percentage of glands producing mucin and the morphology of the different tumor cell types in mucin pools. We retrospectively analyzed the prognosis of 43 patients with stage II/III. The overall frequencies of KRAS and BRAF mutations were 36% and 8%, respectively. Patients with MAC exhibiting high levels of mucin were related to the increase of tumor diameter (P=0.038) but were not associated with any of the other clinicopathologic parameters. The proportion or variable morphology of mucinous component did not stratify progression-free survival in stage II/III cases. TIL was the most significant predictor of progression-free survival among stage II/III CAWMC. It is interesting to note that signet ring cell carcinoma does not portend a worse prognosis for patients with high TIL levels. Combining use the grade of TIL status with the WHO grade of the entire tumor can help identify patients with a high risk of recurrence more accurately.

Survival effect of probiotics in a rat model of colorectal cancer treated with capecitabine

BACKGROUND

Probiotics are used to manage a number of gastrointestinal disorders due to their beneficial properties. Clinical reports showed that probiotics also improve the life quality of patients with colorectal cancer (CRC) subjected to oncologic treatment. In a CRC animal model, probiotics supplementation has the potential to decrease the formation of aberrant crypts and ameliorate tumor malignancy, enhancing the antitumor effect of 5-fluorouracil (5-FU) chemotherapy. Based on these data, we hypothesize that the administration of probiotics impact positively in the overall survival and life quality of rats with CRC under the treatment of capecitabine, which is the pro drug of 5-FU.

AIM

To evaluate the probiotics effects in a rat CRC model treated with capecitabine and followed until the end of life.

METHODS

1,2-Dimethylhidrazine dihydrochloride (1,2-DMH) was employed as carcinogen inductor of CRC. Fifty male Wistar-Lewis rats were randomly assigned to one of five following groups: Control (n = 5), Control + probiotics (Control-P group, n = 5), 1,2-DMH alone (DMH group, n = 10), 1,2-DMH + capecitabine (DMH-C group, n = 10), 1,2-DMH + probiotics (DMH-P group, n = 10) and 1,2-DMH + capecitabine + probiotics (DMH-C-P group, n = 10). All parametric data were expressed as the mean ± SD. The statistical significance of differences was analyzed using one-way ANOVA. Data were analyzed with InfoStat software. The results were considered statistically significant at P < 0.05. Overall survival was evaluated with the Kaplan-Meier estimator with the log-rank test.

RESULTS

The data of mean overall survival for DMH, DMH-P, DMH-C, DMH-C-P, Control and Control-P groups were 250 d [95% confidence interval (CI): 242.5-253.1], 268 d (95%CI: 246.3-271.4), 380 d (95%CI: 337.8-421.9), 480 d (95%CI: 436.9-530.7), 588 d (95%CI: 565.8-609.3) and 590 d (95%CI: 564.3-612.9), respectively, with a significant difference between DMH-C and DMH-C-P groups (P = 0.001). Comparing all groups by Kaplan-Meier estimator, we found a significantly different in the overall survival of DMH and DMH-P groups respect to DMH-C (P = 0.001) and DMH-C-P (P = 0.001) groups; interestingly, there were no meaningful differences between Control, Control-P and DMH-C-P groups (P = 0.012). The tendency of change in body weight gain of the rats at 90 d of finishing DMH administration was similar in Control group compared with DMH-C and DMH-C-P groups; however, and of relevance, DMH-C-P group has experienced a higher body weight gain at the end of animal’s life than DMH-C group (P = 0.001). In DMH-C-P group we found a positive effect of probiotics in clinical manifestations since diarrhea, constipation and blood stool were absenting. Also, the tumor burden was lower in DMH-C-P than DMH-C, DMH-P or DMH groups (1.25 vs 1.81 vs 3.9 vs 4.8 cm², respectively). DMH-C and DMH-C-P groups showed only mucinous carcinoma type while in other DMH groups the tumor types were variable. However, mucinous carcinoma from DMH-C-P group showed invasion until muscularis propria layer. Interestingly, metastatic lymph node was observed in DMH, DMH-C and DMH-P groups but not in DMH-C-P. All animals in Control group died from natural causes without objective injuries. All animals of DMH and DMH-P groups died from tumor complications (i.e., obstruction or intestinal perforation); however, this cause was seen only in 44.5% of DMH-C and DMH-C-P groups

CONCLUSION

Probiotics administration improves life quality of rats with CRC under capecitabine treatment and also has a positive effect in the overall survival of these animals treated with this drug.

Mucinous and non-mucinous colorectal cancers show differential expression of chemotherapy metabolism and resistance genes

Previous research has identified differences in mutation frequency in genes implicated in chemotherapy resistance between mucinous and non-mucinous colorectal cancers (CRC). We hypothesized that outcomes in mucinous and non-mucinous CRC may be influenced by expression of genes responsible for chemotherapy resistance. Gene expression data from primary tumor samples were extracted from The Cancer Genome Atlas PanCancer Atlas. The distribution of clinical, pathological, and gene expression variables was compared between 74 mucinous and 521 non-mucinous CRCs. Predictors of overall survival (OS) were assessed in a multivariate analysis. Kaplan-Meier curves were constructed to compare survival according to gene expression using the log rank test. The median expression of 5-FU-related genes TYMS, TYMP, and DYPD was significantly higher in mucinous CRC compared to non-mucinous CRC (p < 0.001, p = 0.003, p < 0.001, respectively). The median expression of oxaliplatin-related genes ATP7B and SRPK1 was significantly reduced in mucinous versus non-mucinous CRC (p = 0.004, p = 0.007, respectively). At multivariate analysis, age (odds ratio (OR) = 0.96, p < 0.001), node positive disease (OR = 0.49, p = 0.005), and metastatic disease (OR = 0.32, p < 0.001) remained significant negative predictors of OS, while high SRPK1 remained a significant positive predictor of OS (OR = 1.59, p = 0.037). Subgroup analysis of rectal cancers demonstrated high SRPK1 expression was associated with significantly longer OS compared to low SRPK1 expression (p = 0.011). This study highlights that the molecular differences in mucinous CRC and non-mucinous CRC extend to chemotherapy resistance gene expression. SRPK1 gene expression was associated with OS, with a prognostic role identified in rectal cancers.

Patient-derived tumor-like cell clusters for drug testing in cancer therapy

Several patient-derived tumor models emerged recently as robust preclinical drug-testing platforms. However, their potential to guide clinical therapy remained unclear. Here, we report a model called patient-derived tumor-like cell clusters (PTCs). PTCs result from the self-assembly and proliferation of primary epithelial, fibroblast, and immune cells, which structurally and functionally recapitulate original tumors. PTCs enabled us to accomplish personalized drug testing within 2 weeks after obtaining the tumor samples. The defined culture conditions and drug concentrations in the PTC model facilitate its clinical application in precision oncology. PTC tests of 59 patients with gastric, colorectal, or breast cancers revealed an overall accuracy of 93% in predicting their clinical outcomes. We implemented PTC to guide chemotherapy selection for a patient with mucinous rectal adenocarcinoma who experienced recurrence with metastases after conventional therapy. After three cycles of a nonconventional therapy identified by the PTC, the patient showed a positive response. These findings need to be validated in larger clinical trials, but they suggest that the PTC model could be prospectively implemented in clinical decision-making for therapy selection.

Clinical significance of a microRNA signature for the identification and predicting prognosis in colorectal cancers with mucinous differentiation

Accumulating evidence supports the fact that the mere presence of mucinous differentiation in colorectal cancer (CRC), rather than its proportion, is a more accurate representative of a particular CRC subtype with distinct clinical and molecular features. In addition, the prognostic significance of the mucinous carcinoma (MC) subtype remains poorly understood and biomarkers have been barely explored in this disease. Herein, we have performed a systematic and comprehensive analysis in MCs and non-MCs and identified a panel of microRNAs (miRNAs) that are differentially expressed between these two subtypes of CRC. Next, we interrogated their clinical significance and demonstrated their robust diagnostic and prognostic clinical ability in CRCs with mucinous differentiation. Finally, we established an integrative risk-assessment model by combining the miRNA-based risk scores together with TNM staging, which was a superior predictor of prognosis in mucinous CRC patients. Collectively, we report a novel miRNA biomarker panel for the identification and predicting survival in CRC patients with mucinous differentiation.

Distinct Genomic Landscape of Colorectal Mucinous Carcinoma Determined via Comprehensive Genomic Profiling: Steps to a New Treatment Strategy

Colorectal mucinous carcinoma (MC) is associated with inferior prognosis and response to treatment compared to adenocarcinoma (AC). The molecular landscapes of MC and adenocarcinoma with mucous composition (AMC) are not well-defined. We aimed to describe the genomic landscape of MC and AMC in a large colorectal cancer cohort. Tumor samples from patients with MC, AMC, or AC were analyzed using next-generation sequencing. MC had a molecular signature distinct from that of AC; genomic features were similar between AMC and MC but not between AMC and AC. HER2 amplification and TP53 and APC mutation rates were lower, whereas SMAD4, PIK3CA, ACVR2A, KMT2D, LRP1, TGFBR2, GRIN2A, BRAF V600E, PTEN, and BRCA2 mutation rates were higher in MC than in AC. The mutation frequencies in MAPK, PI3K, and TGF- pathways were higher, whereas those of cell cycle proteins and Wnt were lower in MC and AMC than in AC. The proportion of hypermutated tumors was significantly higher in MC and AMC than in AC. As MC has a distinct molecular signature from AC, immunotherapy can be potentially applied in treating MC. Similar molecular profiles of AMC and MC suggest that treatment strategies for MC, but not AC, can be used for AMC treatment.

The genomic landscape of carcinomas with mucinous differentiation

Mucinous carcinomas can arise in any organ with epithelial cells that produce mucus. While mucinous tumors from different organs are histologically similar, it remains to be elucidated whether they share molecular alterations. Here we analyzed a total of 902 patients across six cancer types by comparing mucinous and non-mucinous samples, integrating text mining of pathology reports, gene expression, methylation, mutational and copy-number profiling. We found that, in addition to genes involved in mucin processing and secretion, MUC2 up-regulation is a multi-cancer biomarker of mucinous histology and is regulated by DNA methylation in colorectal, breast and stomach cancer. The majority of carcinomas with mucinous differentiation had fewer DNA copy-number alterations than non-mucinous tumors. The tumor mutational burden was lower in breast and lung with mucinous differentiation compared to their non-mucinous counterparts. We found several differences in the frequency of oncogenic gene and pathway alterations between mucinous and non-mucinous carcinomas, including a lower frequency of p53 pathway alterations in colorectal and lung cancer, and a lower frequency of PI-3-Kinase/Akt pathway alterations in breast and stomach cancer with mucinous differentiation. This study shows that carcinomas with mucinous differentiation originating from different organs share transcriptomic and genomic similarities. These results might pave the way for a more biologically relevant taxonomy for these rare cancers.

First-line therapy of bevacizumab plus chemotherapy versus cetuximab plus chemotherapy for metastatic colorectal cancer patients with mucinous adenocarcinoma or mucinous component

Background

To compare the efficacy of first‐line bevacizumab plus chemotherapy with cetuximab plus chemotherapy based on the stratification of metastatic colorectal cancer (mCRC) patients with mucinous adenocarcinoma (MA) or mucinous component (MC).

Methods

A retrospective study involving all mCRC patients receiving first‐line bevacizumab‐based or cetuximab‐based chemotherapy at our hospital from September 2013 to January 2020 was conducted. Overall survival (OS), progression‐free survival (PFS), and objective response rate (ORR) were compared between the cetuximab‐chemotherapy group and the bevacizumab‐chemotherapy group on the basis of the conventional pathological classification of MA or MC.

Results

A total of 620 patients with mCRC were included in our study, consisting of 141 (22.7%) patients with MA/MC and 479 (77.3%) patients with non‐mucinous adenocarcinoma (NMA). In the MA/MC cohort, patients who were treated with bevacizumab‐based chemotherapy were associated with significantly better OS than those treated with cetuximab‐base chemotherapy (30.0 vs. 26.3 months, p = 0.002), irrespective of tumor sites. The efficacy of bevacizumab‐based chemotherapy was higher in nearly all subgroups as shown in the subgroup analysis. In the NMA cohort, median OS was better in the cetuximab plus chemotherapy group than that in the bevacizumab plus chemotherapy group (32.2 vs. 27.0 months, p = 0.005) for left‐side mCRC patients, whereas OS was significantly longer in the bevacizumab plus chemotherapy group for right‐side mCRC patients (26.0 vs. 20.9 months, p = 0.013).

Conclusion

Conventional pathological classification (e.g. MA/MC) should be considered when tailoring the individualized optimal treatment for mCRC. Bevacizumab plus chemotherapy as first‐line therapy may be the optimal option for patients with MA/MC.

Resistance to Cell Death in Mucinous Colorectal Cancer-A Review

Mucinous colorectal cancer (CRC) is estimated to occur in approximately 10-15% of CRC cases and is characterized by abundant extracellular mucin. Mucinous CRC is frequently associated with resistance to apoptosis. Inferior prognosis is observed in mucinous CRC, particularly in rectal cancer and metastatic cases. Mucins are heavily glycosylated secretory or transmembrane proteins that participate in protection of the colonic epithelium. MUC2 overexpression is a hallmark of mucinous CRCs. Mucinous CRC is associated with KRAS and BRAF mutation, microsatellite instability and the CpG island methylator phenotype. Mutations of the APC gene and p53 mutations which are characteristic non-mucinous colorectal adenocarcinoma are less common in mucinous CRC. Both physical and anti-apoptotic properties of mucin provide mechanisms for resistance to cell death. Mucin glycoproteins are associated with decreased expression of pro-apoptotic proteins, increased expression of anti-apoptotic proteins and increased cell survival signaling. The role for BCL-2 proteins, including BCL-X_L, in preventing apoptosis in mucinous CRC has been explored to a limited extent. Additional mechanisms opposing cell death include altered death receptor expression and altered mutation rates in genes responsible for chemotherapy resistance. The roles of alternate cell death programs including necroptosis and pyroptosis are not well understood in mucinous CRC. While the presence of MUC2 is associated with an immunosuppressive environment, the tumor immune environment of mucinous CRC and the role of immune-mediated tumor cell death likewise require further investigation. Improved understanding of cell death mechanisms in mucinous CRC may allow modification of currently used regimens and facilitate targeted treatment.

Prognostic significance of BIRC7/Livin, Bcl-2, p53, Annexin V, PD-L1, DARC, MSH2 and PMS2 in colorectal cancer treated with FOLFOX chemotherapy with or without aspirin

Evasion of apoptosis is associated with treatment resistance and metastasis in colorectal cancer (CRC). Various cellular processes are associated with evasion of apoptosis. These include overexpression of pro-apoptotic proteins (including p53 and PD-L1), anti-apoptotic proteins (BIRC7/Livin and Bcl-2), chemokine receptors (including DARC), and dysregulation of DNA mismatch repair proteins (including MSH2 and PMS2). The aim of this study was to determine the effect of folinic acid, 5-FU and oxaliplatin (FOLFOX) as a single agent and aspirin plus FOLFOX in various combinations on the aforementioned proteins in human CRC, SW480 cell line and rat models of N-Methyl-N-Nitrosourea (NMU)-induced CRC. In addition, effects of the NMU-induced CRC and chemotherapeutic regimens on haematological and biochemical parameters in the rat models were studied. Immunohistochemistry, immunofluorescence and immunoblot techniques were used to study the expression pattern of the related proteins in the human CRC cells pre- and post-treatment. Double contrast barium enema, post-mortem examination and histological analyses were used to confirm tumour growth and the effect of the treatment in vivo in rat models. Notably, we found in human mucinous CRC, a significant increase in expression of the BIRC7/Livin post-FOLFOX treatment compared with pre-treatment (p = 0.0001). This increase provides new insights into the prognostic role of BIRC7/Livin in evasion of apoptosis and facilitation of treatment resistance, local recurrence and metastasis particularly among mucinous CRCs post-FOLFOX chemotherapy. These poor prognostic features in the CRC may be further compounded by the significant suppression of DARC, PD-L1, PMS2 and overexpression of MSH2 and anti-apoptotic Bcl-2 and p53 proteins observed in our study (p < 0.05). Importantly, we found a significant reduction in expression of BIRC7/Livin and reactivation of DARC and PD-L1 with a surge in Annexin V expression in rat models of CRC cells post-treatment with a sequential dose of aspirin plus FOLFOX compared with other treatments in vivo (p <0.05). The mechanistic rational of these effects underscores the importance of expanded concept of possible aspirin combination therapy with FOLFOX sequentially in future CRC management. Validation of our findings through randomized clinical trials of aspirin plus FOLFOX sequentially in patients with CRC is therefore warranted.

Outcomes of Laparoscopic Surgery for Mucinous Colorectal Adenocarcinoma

Background: Mucinous colorectal adenocarcinoma (MAC) has a higher incidence of local extension, leading to lower overall resection rates. Few studies have investigated the outcomes of laparoscopic surgery for MACs to date. Therefore, we aimed to elucidate the validity of laparoscopic surgery for mucinous adenocarcinoma (MAC). Methods: This study analyzed short-term and long-term outcomes between laparoscopic and open surgery for MACs from 2008 to 2018. Multivariate analyses were used to define prognostic factors of overall survival (OS) and disease-free survival (DFS). Results: Patients in the laparoscopy (LAP) group had significantly less blood loss, fewer days to first flatus and to diet, and shorter length of hospital stay. The 3-year and 5-year DFS rates for all stages combined were 65.7% and 62.5% in the LAP group compared with 60.5% and 57.6% in the open (OPEN) surgery group (P = .521). The 3-year and 5-year OS rates for all stages combined were 72.3% and 67.3% in the LAP group compared with 72.6% and 67.8% in the OPEN group (P = .934). OS and DFS in stage II, stage III, and pathological T4 (pT4) stage patients who underwent laparoscopic surgery did not differ from patients who underwent open surgery. Multivariate analysis showed that stage pT4, pN2, and carcinoembryonic antigen (CEA) were significant predictors of OS. Independent factors, including intraoperative blood transfusion, stage pT4, pN2, CEA, and CA19-9, carbohydrate antigen 19-9, have a great effect on DFS. Conclusions: Laparoscopic surgery is a safe and feasible option for mucinous colorectal AC, which provides faster postoperative recovery and less intraoperative blood loss.

Prognostic implications of mucinous histology in stage III colon cancer with the receipt of adjuvant chemotherapy

Background

There is still a debate about the survival benefit of chemotherapy in stage III mucinous colon cancer, we then conduct a comprehensive assessment of the efficacy of adjuvant chemotherapy in this population.

Methods

The data used in the current study were extracted from the Surveillance, Epidemiology and End Results (SEER) database. Chi-squared (χ²) test was used to compared patient characteristics according to the histology. The outcome of the survival analysis used in the current study was cancer-specific survival (CSS). Univariable and multivariable analyses were carried out using the Cox proportional hazards regression models to evaluate the prognostic characteristics associated with CSS of colon cancer. And the risks of mortality were presented as hazard ratios (HRs) with 95% confidence intervals (CIs).

Results

A total of 68,976 patients diagnosed with stage III colon cancer were included in our analyses, including mucinous adenocarcinoma (MAC, N=6,592) and non-mucinous adenocarcinoma (NMA, N=62,384). In NMA, the receipt of chemotherapy had 46.0% independently decreased risk of colon cancer-specific mortality compared to non-chemotherapy group (HR =0.540, 95% CI: 0.523-0.558, P<0.001). In MAC, the receipt of chemotherapy had 37.7% independently decreased risk of colon cancer-specific mortality compared to non-chemotherapy group (HR =0.623, 95% CI: 0.566-0.685, P<0.001).

Conclusions

MAC was associated with worse prognosis and was less responsive to chemotherapy compared with NMA in stage III colon cancer. However, stage III mucinous colon cancer still need to be treated with chemotherapy because of the significant survival benefit and specialized treatment plans for MAC were quite necessary in the future.

Mucinous Adenocarcinoma of the Rectum: A Whole Genome Sequencing Study

Introduction

Mucinous adenocarcinoma of the rectum is an infrequently encountered histological subtype that is associated with an impaired response to chemoradiotherapy and a worse overall prognosis. A genomic profile analysis of mucinous rectal tumors has not yet been performed. The aim of this study was to comprehensively describe the burden of somatic mutations and copy number variation as well as perform mutational signature and microbial analysis of an in-house collected cohort of mucinous adenocarcinoma of the rectum.

Methods

Genomic DNA was extracted from 10 cases of mucinous rectal cancer and matched normal tissue. Whole genome sequencing (WGS) was carried out on these 10 cases and a comprehensive bioinformatic analysis was undertaken.

Results

The average number of SNVs, InDels and SVs in the cohort was 16,600, 1,855, and 120, respectively. A single case was MSI-H. KRAS mutations were found in 70% of cases while TP53 was mutated in only 40% of cases. CNA gain was identified on chromosomes 7, 8, 12, 13, and 20 while CNA loss was found on chromosomes 4, 8, 17, and 18 corresponding to oncogenes and tumor suppressor genes, respectively. Overall mucinous rectal cancers are more likely to be MSI-H and to have KRAS, BRAF, and PIK3CA mutations when compared to rectal adenocarcinoma NOS. Microbial analysis demonstrated an abundance of Fusobacterium nucleatum in tumor samples compared to normal tissue.

Conclusion

This study provides a detailed WGS analysis of 10 cases of mucinous rectal cancer. It demonstrates an important lesson in tumor biology in that histologically similar tumors can have extensive differences at the genomic level. This study is relevant as it raises important questions about the relationship between bacteria and malignancy.

Synergistic apoptosis following endoplasmic reticulum stress aggravation in mucinous colon cancer

Background

Mucinous colon cancers (MCC) are characterized by abundant production of mucin 2 (MUC2) protein and are less sensitive to standard systemic chemotherapy. We postulated that severe/persistent endoplasmic reticulum stress (ERS) aggravation in MCC would overwhelm compensatory cytoprotective pathways and induce apoptosis.

Results

Basal levels of ERS markers were higher in MCC and dnTCF-LS174T cells than non-mucinous tumors and these levels were significantly increased by combinatorial treatment with ERS aggravators celecoxib + orlistat. Combination treatment inhibited cell viability and synergistically induced apoptosis. Treatment-induced cell death was ERS-dependent, apoptotic pathways were not activated following knockdown of ERS protein CHOP. Dual drug treatment significantly reduced mucinous tumor growth in vivo and induced ERS and apoptosis, consistent with in vitro experiments.

Conclusions

Novel therapies are needed since MCC are more resistant to standard systemic chemotherapy. This study suggests ERS aggravation is a viable therapeutic strategy to reduce tumor growth in MCC.

Genomic, Transcriptomic, Epigenetic, and Immune Profiling of Mucinous Breast Cancer

Although invasive ductal breast cancer (IDC) represents the most common histological type of breast cancer, minor subtypes exist such as mucinous breast cancer (MuBC). MuBC are distinguished by tumor cells floating in extracellular mucin. MuBC patients are generally older and associated with a favorable prognosis. To unravel the molecular architecture of MuBC, we applied low-pass whole-genome sequencing and microscopic evaluation of stromal tumor infiltrating lymphocytes to 30 MuBC from a retrospective institutional cohort. We further analyzed two independent datasets from the International Cancer Genomics Consortium and The Cancer Genome Atlas. Genomic data (n = 26 MuBC, n = 535 estrogen receptor [ER] positive/HER2-negative IDC), methylation data (n = 28 MuBC, n = 529 ER-positive/HER2-negative IDC), and transcriptomic data (n = 27 MuBC, n = 467 ER-positive/HER2-negative IDC) were analyzed. MuBC was characterized by low tumor infiltrating lymphocyte levels (median = 0.0%, average = 3.4%, 95% confidence interval = 1.9% to 4.9%). Compared with IDC, MuBC had a lower genomic instability (P = .01, two-sided Mann-Whitney U test) and a decreased prevalence of PIK3CA mutations (39.7% in IDC vs 6.7% in MuBC, P = .01 in the International Cancer Genomics Consortium; and 34.8% vs 0.0%, P = .02 in The Cancer Genome Atlas, two-sided Fisher's exact test). Finally, our report identifies aberrant DNA methylation of MUC2 as a possible cause of extracellular production of mucin in MuBC.

Clinicopathological Characteristics and Mutation Spectrum of Colorectal Adenocarcinoma With Mucinous Component in a Chinese Cohort: Comparison With Classical Adenocarcinoma

Background: Colorectal adenocarcinoma with mucinous component (AWMC) is a special entity of colorectal cancer. The study is aimed at analyzing the clinicopathological characteristics, mutation spectrum, and prognosis of AWMC and comparing it with classical adenocarcinoma (AC) in a Chinese cohort. Methods: One hundred eight AMWC and 204 AC patients were included. Targeted next-generation sequencing (NGS) was performed on formalin-fixed paraffin-embedded (FFPE) tissues. AWMC was further divided into two groups: AWMC with signet ring cell component and AWMC without signet ring cell component. Clinicopathological features, mismatch repair protein (MMR) status, genetic alterations, and survival outcomes were analyzed after tumor location was taken into consideration. Results: AWMC had larger tumor size (p = 0.014) and showed predilection for proximal colon (p < 0.001) compared with AC. Regardless of primary sites, AWMC was associated with less metastasis (p < 0.001) and earlier AJCC stage (p < 0.001). Mismatch repair protein deficiency (dMMR) was more commonly detected in AWMC than in AC for right-sided colon (p < 0.001), but the difference was not significant for left-sided colon (p = 0.081). The five most commonly mutated genes in AWMC were KRAS (45.4%), TP53 (39.8%), APC (22.2%), PIK3CA (22.2%), and SMAD4 (10.2%). AWMC showed a significantly lower mutation rate of TP53 than AC, both in right-sided colon and in left-sided colon (p < 0.001 and p = 0.033, respectively). In left-sided colon, AWMC with signet ring cell component had a significantly smaller size than tumors with signet ring cell component (p = 0.034). No dMMR cases were detected in AWMC with signet ring cell component (n = 7). Moreover, AWMC with signet ring cell component had a significantly lower KRAS mutation rate than AWMC without signet ring cell component, both in right-sided colon and in left-sided colon (p = 0.036 and p = 0.012, respectively). The disease-specific survival (DSS) for AWMC and AC were not statistically different (p = 0.0587). Multivariate analysis showed that AWMC was not an independent predictor of prognosis. Conclusion: Regardless of primary sites, AWMC demonstrates less metastasis, earlier stages, more frequent dMMR, and lower TP53 mutation rate than AC. Our results indicate that different molecular pathogenesis might underlie mucinous morphology in colorectal carcinoma. Mucinous component is not an independent factor of outcome.

Sequential Ras/MAPK and PI3K/AKT/mTOR pathways recruitment drives basal extrusion in the prostate-like gland of Drosophila

One of the most important but less understood step of epithelial tumourigenesis occurs when cells acquire the ability to leave their epithelial compartment. This phenomenon, described as basal epithelial cell extrusion (basal extrusion), represents the first step of tumour invasion. However, due to lack of adequate in vivo model, implication of emblematic signalling pathways such as Ras/Mitogen-Activated Protein Kinase (MAPK) and phosphoinositide 3 kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signalling pathways, is scarcely described in this phenomenon. We have developed a unique model of basal extrusion in the Drosophila accessory gland. There, we demonstrate that both Ras/MAPK and PI3K/AKT/mTOR pathways are necessary for basal extrusion. Furthermore, as in prostate cancer, we show that these pathways are co-activated. This occurs through set up of Epidermal Growth Factor Receptor (EGFR) and Insulin Receptor (InR) dependent autocrine loops, a phenomenon that, considering human data, could be relevant for prostate cancer.

The molecular mechanisms leading to basal extrusion are unclear. Here, the authors use the Drosophila accessory gland to model human prostate acini and show that Ras/MAPK and PI3K/AKT/mTOR pathways are co-activated in two autocrine loops by dEGF and dIGF, inducing basal extrusion and subsequent tumour formation.

Rational application of targeted therapeutics in mucinous colon/appendix cancers with positive predictive factors

Molecular‐targeted therapies have demonstrated disappointing results against most advanced solid cancers. This may largey be attributed to irrational drug use against unselected cancers. We investigated the efficacy of dual MEK‐PI3K drug therapy against KRAS mutated mucin 2 (MUC2)‐secreting LS174T cells and patient‐derived ex vivo and in vivo models of KRAS mutated mucinous colon/appendix cancers. These tumors demonstrate unique phenotypic and genotypic features that likely predict sensitivity to this targeted co‐therapy. Co‐treatment with MEK inhibitor (trametinib) and PI3K inhibitor (pictilisib)‐induced synergistic cytotoxicity and intrinsic mitochondrial‐mediated apoptosis in LS174T cells and tumor explants in vitro. Dual drug therapy also induced endoplasmic reticulum stress (ERS)‐associated proteins (GRP78/BiP, ATF4, and CHOP). However, CHOP knock‐down assays demonstrated that mitochondrial‐mediated apoptosis in LS174T cells was not ERS‐dependent. Dual drug therapy also significantly decreased MUC2 expression, MUC2 post‐translational modification (palmitoylation) and secretion in LS174T cells, suggesting a simultaneous cytotoxic and mucin suppressive mechanism of action. We also demonstrated effective mucinous tumor growth suppression in ex vivo epithelial organoid (colonoid) cultures and in in vivo intraperitoneal patient‐derived xenograft models derived from mucinous colon/appendix cancer. These promising preclinical data support a role for dual MEK‐PI3K inhibitor therapy in mucinous colon/appendix cancers. We postulate that mucinous KRAS mutated cancers are especially vulnerable to this co‐treatment based on their unique phenotypic and genotypic characteristics.

Tumor clinicopathological characteristics and their prognostic value in mucinous colorectal carcinoma

Aim: This study analyzed clinicopathological features of colorectal mucinous carcinoma and their prognostic values. Patients & method: This study enrolled 265 patients with mucinous colorectal cancer. Clinicopathological information and prognosis were reviewed retrospectively. Kaplan-Meier method, log- rank test and COX proportional hazard regression models were used. Results: In postoperative mucinous carcinoma patients (median age 56, 119 [44.9%] female), advanced tumor stage (odds ratio [OR]: 2.378; 95% CI: 1.512-3.741; p = 0.0002), poor differentiation (OR: 1.896; CI: 1.217-2.955; p = 0.0047) and right-sided tumors (OR: 2.421; CI: 1.145-5.102; p = 0.0206) were associated with shorter overall survival. Appendiceal/ileocecal cecal tumors were not different for prognosis. Conclusion: Mucinous colorectal carcinoma exhibits distinct tumor characteristics. Poor differentiation, advanced stage at presentation and the right side serve as negative prognostic factors.

Mucinous adenocarcinoma of the colon and rectum: A genomic analysis

BACKGROUND AND OBJECTIVES

Mucinous adenocarcinoma is a distinct subtype of colorectal cancer (CRC) with a worse prognosis when compared with non-mucinous adenocarcinoma. The aim of this study was to compare somatic mutations and copy number alteration (CNA) between mucinous and non-mucinous CRC.

METHODS

Data from The Cancer Genome Atlas-colon adenocarcinoma and rectum adenocarcinoma projects were utilized. Mucinous and non-mucinous CRC were compared with regard to microsatellite status, overall mutation rate, the most frequently mutated genes, mutations in genes coding for mismatch repair (MMR) proteins and genes coding for mucin glycoproteins. CNA analysis and pathway analysis was undertaken.

RESULTS

Mucinous CRC was more likely to be microsatellite instability-high (MSI-H) and hypermutated. When corrected for microsatellite status the single-nucleotide variation and insertion-deletion rate was similar between the two cohorts. Mucinous adenocarcinoma was more likely to have mutations in genes coding for MMR proteins and mucin glycoproteins. Pathway analysis revealed further differences between the two histological subtypes in the cell cycle, RTK-RAS, transforming growth factor-β, and TP53 pathways.

CONCLUSIONS

Mucinous CRC has some distinct genomic aberrations when compared with non-mucinous adenocarcinoma, many of which are driven by the increased frequency of MSI-H tumors. These genomic aberrations may play an important part in the difference seen in response to treatment and prognosis in mucinous adenocarcinoma.

Discrimination of low- and high-grade appendiceal mucinous neoplasms by targeted sequencing of cancer-related variants

DNA was obtained from matching micro-dissected, primary tumor cells, paired metastases, and peripheral blood mononuclear cells (germline) from patients with appendiceal mucinous neoplasms. We compared specimens from patient cohorts comprising low-grade adenomucinous neoplasm versus high-grade mucinous adenocarcinoma using a targeted, amplicon sequencing panel of 409 cancer related genes (Ion Torrent Comprehensive Cancer Panel, Thermo-Fisher, Waltham, MA). Copy number variants, single nucleotide variants and small insertions/deletions were identified using a multiplex algorithm pipeline (GATK, VarScan2, MuTect2, SIFT, SIFT-INDEL, PolyPhen-2, Provean). There were significantly more damaging variants in high-grade versus low-grade tumor cohorts. Both cohorts contained damaging, heterozygous germline variants (catenin β1; notch receptor 1 and 4) in pathways associated with cell-lineage specification (WNT, NOTCH). Damaging, somatic KRAS proto-oncogene, GTPase mutations were present in both cohorts, while somatic GNAS complex locus mutations were confined to low-grade neoplasms. Variants predominantly affected transcription factors, kinases, and stem cell signaling molecules in canonical pathways including epithelial to mesenchymal transition, stem cell pluripotency, p53, PTEN, and NF-қB signaling pathways. High-grade tumors demonstrated MYC proto-oncogene, bHLH transcription factor (MYC) and death domain associated protein (DAXX) amplification and damaging somatic variants in tumor protein p53 (TP53), likely to amplify an aggressive phenotype. Damaging APC, WNT signaling pathway regulator (APC) deletions were identified in metastatic tissue of both cohorts suggesting a role in invasive disease. Our data suggest that germline dysregulation of WNT and/or NOTCH pathways predisposes patients toward a secretory cell phenotype (i.e., goblet-like cells) upon acquisition of somatic KRAS mutations. Additional somatically acquired variants activating oncogenes MYC and DAXX and inhibiting the critical tumor suppressor, tumor protein TP53, were consistent with manifestation of a high-grade phenotype. These additional changes within the epithelial to mesenchymal transition signaling network (WNT, NOTCH, RAS/ERK/PI3K, PTEN, NF-қB), produce aggressive high-grade tumor characteristics by actively driving cells towards dedifferentiation, proliferation, and migration.

RAS Mutation in Mucinous Carcinoma of the Ovary

Objective: This study was designed to identify genetic mutation in mucinous carcinoma of the ovary of the patients in King Chulalongkorn Memorial hospital, Bangkok, Thailand and study the relationship between genetic mutation and patients’ prognosis. Methods: Fifty cases of primary mucinous carcinoma of the ovary were selected. DNA was analyzed for genetic mutation using ColoCarta Panel v1.0 and MassArray® System. Demographic data and clinical information of the participants were reviewed from electronic medical records and government data services. Results: Median of disease-free survival is 171.33 +/- 9.04 months and the median overall survival is 171.37 +/- 9.03 months. Twelve percent of the participants had recurrence and all of recurrent cases died from disease or its complication. We found three mutations which were KRAS (27 cases, 54%), PIK3CA (4 cases, 8%) and BRAF (1 case, 2%). Among the KRAS-mutated patients, the majority of the cases (25 cases, 92.6%) were in stage I. Recurrence and disease related mortality were not observed in the KRAS mutated patients. Conclusion: The genetic mutation analysis found three mutations which were KRAS 27 cases (54%), PIK3CA 4 cases (8%) and BRAF 1 case (2%) The ovarian mucinous carcinoma patients with KRAS mutation in our study showed excellent prognosis.

Mucinous colorectal adenocarcinoma: clinical pathology and treatment options

Mucinous colorectal adenocarcinoma is a distinct subtype of colorectal cancer (CRC) characterized by the presence of abundant extracellular mucin which accounts for at least 50% of the tumor volume. Mucinous colorectal adenocarcinoma is found in 10%–20% of CRC patients and occurs more commonly in female and younger patients. Moreover, mucinous colorectal adenocarcinoma is more frequently located in the proximal colon and diagnosed at an advanced stage. Based on its molecular context, mucinous colorectal adenocarcinoma is associated with the overexpression of mucin 2 (MUC2) and mucin 5AC (MUC5AC) proteins. At the same time, it shows higher mutation rates in the fundamental genes of the RAS/MAPK and PI3K/Akt/mTOR pathways. Mucinous colorectal adenocarcinoma also shows higher rates of microsatellite instability (MSI) than non-mucinous colorectal adenocarcinoma which might correlate it with Lynch syndrome and the CpG island methylator phenotype. The prognosis of mucinous colorectal adenocarcinoma as to non-mucinous colorectal adenocarcinoma is debatable. Further, the impaired responses of mucinous colorectal adenocarcinoma to palliative or adjuvant chemotherapy warrant more studies to be performed for a specialized treatment for these patients. In this review, we discuss the molecular background and histopathology of mucinous colorectal adenocarcinoma, and provide an update on its prognosis and therapeutics from recent literatures.

Lack of Benefit From Anti-EGFR Treatment in RAS and BRAF Wild-type Metastatic Colorectal Cancer With Mucinous Histology or Mucinous Component

BACKGROUND

Adenocarcinoma with mucinous histology or mucinous component are histologic subtypes of metastatic colorectal cancers (mCRCs) with limited benefit from cytotoxic agents. Their sensitivity to anti-epithelial growth factor receptors (EGFRs) is not clear.

PATIENTS AND METHODS

The activity and efficacy of anti-EGFRs was retrospectively evaluated among patients with RAS and BRAF wild-type mCRC with or without mucinous histology or mucinous component. Subgroup analyses according to primary tumor location were conducted.

RESULTS

Overall, the study population included 22 mucinous or with mucinous component tumors (11 right- and 11 left-sided tumors) and 83 not mucinous tumors. One patient experienced partial response among mucinous tumors, whereas in the not mucinous group, 42 patients experienced partial response, with an overall response rate of 4% and 51%, respectively (P = .003). The median progression-free survival was 2.8 versus 6.7 months (hazard ratio, 0.28; 95% confidence interval, 0.13-0.59; P < .001), and the median overall survival was 6.5 and 16.7 months (hazard ratio, 0.58; 95% confidence interval, 0.33-1.00; P = .022), for the mucinous and not mucinous groups, respectively. Similar results were observed in subgroup analysis according to primary tumor location.

CONCLUSION

Anti-EGFRs may not provide clinically meaningful benefit in mCRCs with mucinous histology or mucinous component compared with those without mucinous component, irrespective of sidedness.

Associations among histological characteristics and patient outcomes in colorectal carcinoma with a mucinous component

AIMS

Colorectal carcinoma (CRC) often has a mucinous component, with more than 50% mucin by volume defining the mucinous subtype of CRC. The prognostic impact of the mucinous phenotype remains unclear.

METHODS AND RESULTS

We evaluated 224 CRC with at least 5% mucinous component (herein 'mCRC') for patient sex, age, race and outcome; tumour size, location, stage and microsatellite instability (MSI) status; percentage of glands producing mucin; percentage of tumour volume composed of mucin; whether tumoral epithelium floated in mucin pools; tumour budding; signet ring cells (SRCs); and peritumoural inflammation (PI). We related these features to disease-specific survival and compared outcomes to 499 stage-matched, conventional colorectal adenocarcinomas. Factors predicting worse prognosis in mCRC on univariable analysis included non-MSI-high status (P = 0.0008), SRC (P = 0.0017) and lack of PI (P = 0.0034). No parameters were independently associated with outcome after adjusting for tumour stage in multivariate analysis. The percentage of glands producing mucin and percentage tumour volume composed of mucin did not affect prognosis, including at the recommended 50% cut-off for subtyping mCRC. Disease-specific survival for mCRC and adenocarcinomas were similar after accounting for stage.

CONCLUSIONS

Stage-matched mCRCs and adenocarcinomas have similar outcomes, with no prognostic significance to morphological subtyping. Histological characteristics of mCRC, including percentage of tumour volume comprised of mucin, were not predictive of outcome.

Impact of Global DNA Methylation in Treatment Outcome of Colorectal Cancer Patients

Background: Global DNA methylation has an impact in cancer pathogenesis and progression. This study aimed at investigating the impact of global DNA methylation in treatment outcome of Colorectal Cancer (CRC).

Patients and Methods: Global DNA methylation was measured by LC/MS/MS in peripheral blood leucocytes of 102, 48, and 32 Egyptian CRC patients at baseline and after 3 and 6 months of Fluoropyrimidine (FP) therapy respectively, in addition to 32 normal healthy matched in age and sex. The genetic expressions of DNA methyl transferases (DNMTs) were determined and correlated with patients‘ survival using univariate and multivariate methods of analyses.

Results: Egyptian CRC patients had significant global hypomethylation of 5mC level and 5mC % with overexpression of DNMT3A and DNMT3B. Significant higher 5mC levels were shown in patients > 45 years, male gender, T2 tumors, stage II, negative lymph nodes, and absence of metastasis. FP therapy significantly reduced DNA methylation particularly in the subgroups of patients with high DNA methylation level at baseline and good prognostic features. After 3 years of follow up, patients with 5mC % > 8.02% had significant poor overall survival (OS) while, significant better event-free survival (EFS) was found in patients with 5mC level > 0.55. High initial CEA level and presence of metastasis were significantly associated with hazards of disease progression and death.

Conclusion: Global DNA methylation has a significant impact on the treatment outcome and survival of Egyptian CRC patients treated with FP- based therapy.

Prognostic Implications of Mucinous Differentiation in Metastatic Colorectal Carcinoma Can Be Explained by Distinct Molecular and Clinicopathologic Characteristics

BACKGROUND

The mucinous histologic subtype accounts for 5% to 20% of colorectal cancer (CRC) cases but remains poorly characterized. The present study characterized the baseline characteristics, mutational profile, and clinical outcomes of patients diagnosed with mucinous CRC.

MATERIALS AND METHODS

We identified 1877 patients with metastatic CRC with available histologic findings and molecular profiling and summarized the baseline clinical and pathologic characteristics and overall survival (OS) stratified by the histologic type. The data from separate cohorts with consensus molecular subtype (CMS) and CpG island methylator information were also summarized.

RESULTS

The mucinous histologic type was found in 277 of the 1877 patients (14.8%) and was associated with an increased prevalence of microsatellite instability (P < .001) and a right-sided primary (P < .001). An increased frequency of CMS1 (microsatellite instability immune) and lower rates of CMS2 (canonical) were identified, with mucinous compared with nonmucinous adenocarcinoma (P < .0001). Mutations in SMAD4 (P < .001), GNAS (P < .001), ERBB2 (P = .02), BRAF (P < .001), and KRAS (P < .001) occurred at greater frequencies in the mucinous CRC cases, and TP53 (P < .001), APC (P < .001), and NRAS mutations (P = .03) were less common. Univariate (hazard ratio [HR], 1.38; 95% confidence interval [CI], 1.17-1.63; P < .001) and multivariate analysis (HR, 1.36; 95% CI, 1.12-1.64; P = .002) demonstrated that the mucinous histologic type is associated with worse OS. The features associated with the mucinous histologic subtype were independent predictors for shorter OS, including BRAF (HR, 1.74; 95% CI, 1.35-2.25; P < .001) and KRAS (HR, 1.42; 95% CI, 1.22-1.65; P < .001) mutations, right-sided location (HR, 1.20; 95% CI, 1.04-1.39; P = .01), and synchronous metastases (HR, 2.92; 95% CI, 2.49-3.42; P < .001).

CONCLUSION

Compared with nonmucinous adenocarcinoma, the mucinous histologic type is associated with a worse prognosis, even when controlling for known prognostic features. This unique biologic behavior should be considered in the treatment and prognostic assessment of patients with CRC.

Serrated adenocarcinoma morphology in colorectal mucinous adenocarcinoma is associated with improved patient survival

Colorectal mucinous adenocarcinoma (MAC) and serrated adenocarcinoma (SAC) share many characteristics, including right-side colon location, frequent mucin production, and various molecular features. This study examined the frequency of SAC morphology in MACs. We assessed the correlation of SAC morphology with clinicopathological parameters, molecular characteristics, and patient prognosis. Eighty-eight colorectal MACs were collected and reviewed for SAC morphology according to Makinen's criteria. We sequenced KRAS and BRAF, assessed CpG island methylator phenotype (CIMP) frequency, and analyzed DNA mismatch repair enzyme levels using immunohistochemistry in tumor samples. SAC morphology was observed in 38% of MACs, and was associated with proximal location (P=0.001), BRAF mutation (P=0.042), CIMP-positive status (P=0.023), and contiguous traditional serrated adenoma (P=0.019). Multivariate analysis revealed that MACs without both SAC morphology and CIMP-positive status exhibited 3.955 times greater risk of cancer relapse than MACs having both characteristics or either one (P=0.035). Our results show that two MAC groups with distinct features can be identified using Makinen's criteria, and suggest a favorable prognostic role for the serrated neoplastic pathway in colorectal MAC.