Colorectal carcinomas with mucinous differentiation are associated with high frequent mutation of KRAS or BRAF mutations, irrespective of quantity of mucinous component

Epidemiological and clinicopathological features of KRAS, NRAS, BRAF mutations and MSI in Chinese patients with stage I-III colorectal cancer

The selection of appropriate treatment modalities based on the presence or absence of mutations in KRAS, NRAS, BRAF, and the microsatellite instability (MSI) status has become a crucial consensus in colorectal cancer (CRC) therapy. However, the distribution pattern of these genetic mutations and the prevalence of MSI status in Chinese stage I-III CRCs remain unclear. We retrospectively analyzed clinicopathological features, mutations in the KRAS, NRAS, and BRAF genes, as well as MSI status of 411 patients with stage I-III CRC who underwent surgery from June 2020 to December 2022 in the First Affiliated Hospital of Nanjing Medical University. The mutation rates of KRAS, NRAS, and BRAF were 48.9%, 2.2%, and 3.2%, respectively, and the microsatellite instability-high rate was 9.5%. KRAS mutation was independently associated with mucinous adenocarcinoma. Multivariate analysis suggested that tumor location and mucinous adenocarcinoma were independently associated with BRAF mutation. Only T stage was associated with NRAS mutations in the univariate analysis. Multivariate analysis revealed that factors such as larger tumor size, tumor location, younger age, and poor differentiation were independently associated with microsatellite instability-high status. The results illustrate the mutation frequencies of KRAS, NRAS, BRAF genes and MSI status in stage I-III CRC from the eastern region of China. These findings further validate the associations between these genes status and various clinicopathological characteristics.

Clinicopathological characteristics and outcomes of colorectal mucinous adenocarcinoma: a retrospective analysis from China

Background

Mucinous adenocarcinoma (MAC) is a unique subtype of colorectal cancer and its prognostic value remains controversial. This study aimed to compare the clinicopathological characteristics and prognostic differences between patients with MAC and non-mucinous adenocarcinoma (NMAC).

Methods

674 patients with NMAC, 110 patients with adenocarcinoma with mucinous component (ACWM) and 77 patients with MAC between 2016-2019 were enrolled in the study. Univariate and multivariate Cox regression were performed to analyze the factors associated with prognosis. Predictive nomograms of overall survival (OS) and cancer-specific survival (CSS) for patients with colorectal adenocarcinoma were constructed. Confounding factors were eliminated by propensity score matching (PSM).

Results

Compared with patients with NMAC, patients with MAC were more likely to have a tumor located at the proximal colon, present with a larger tumor diameter, more advanced T stage, higher frequency of metastasis, deficiency of mismatch repair, and elevated preoperative carcinoembryonic antigen. Patients with MAC were related to worse OS (HR=2.53, 95%CI 1.73-3.68, p<0.01) and CSS (HR=3.09, 95%CI 2.10-4.57, p<0.01), which persisted after PSM. Subgroup analysis demonstrated that patients with left-sided or stage III/IV MAC exhibited a comparatively worse OS and CSS than those with NMAC. Furthermore, in patients with stage II with a high-risk factor and stage III MAC, adjuvant chemotherapy was associated with an improved OS, CSS, and RFS.

Conclusion

Compared with the NMAC phenotype, the MAC phenotype was an independent risk factor for poor prognosis in colorectal adenocarcinoma with worse OS and CSS, particularly patients with left-sided colorectal cancer and stage III/IV. However, patients with MAC can still benefit from adjuvant chemotherapy.

Single-cell multi-omics reveals insights into differentiation of rare cell types in mucinous colorectal cancer

Neuroendocrine cells have been implicated in therapeutic resistance and worse overall survival in many cancer types. Mucinous colorectal cancer (mCRC) is uniquely enriched for enteroendocrine cells (EECs), the neuroendocrine cell of the normal colon epithelium, as compared to non-mucinous CRC. Therefore, targeting EEC differentiation may have clinical value in mCRC. Here, single cell multi-omics was used to uncover epigenetic alterations that accompany EEC differentiation, identify STAT3 as a novel regulator of EEC specification, and discover a rare cancer-specific cell type with enteric neuron-like characteristics. Further experiments demonstrated that lysine-specific demethylase 1 (LSD1) and CoREST2 mediate STAT3 demethylation and regulate STAT3 chromatin binding. Knockdown of CoREST2 in an orthotopic xenograft mouse model resulted in decreased primary tumor growth and lung metastases. In culmination, these results provide rationale for new LSD1 inhibitors that target the interaction between LSD1 with STAT3 or CoREST2, which may improve clinical outcomes for patients with mCRC.

Machine-Learning Identifies a Strategy for Differentiation Therapy in Solid Tumors

BACKGROUND

Although differentiation therapy can cure some hematologic malignancies, its curative potential remains unrealized in solid tumors. This is because conventional computational approaches succumb to the thunderous noise of inter-/intratumoral heterogeneity. Using colorectal cancers (CRCs) as an example, here we outline a machine learning(ML)-based approach to track, differentiate, and selectively target cancer stem cells (CSCs).

METHODS

A transcriptomic network was built and validated using healthy colon and CRC tissues in diverse gene expression datasets (~5,000 human and >300 mouse samples). Therapeutic targets and perturbation strategies were prioritized using ML, with the goal of reinstating the expression of a transcriptional identifier of the differentiated colonocyte, CDX2, whose loss in poorly differentiated (CSC-enriched) CRCs doubles the risk of relapse/death. The top candidate target was then engaged with a clinical-grade drug and tested on 3 models: CRC lines in vitro, xenografts in mice, and in a prospective cohort of healthy (n = 3) and CRC (n = 23) patient-derived organoids (PDOs).

RESULTS

The drug shifts the network predictably, induces CDX2 and crypt differentiation, and shows cytotoxicity in all 3 models, with a high degree of selectivity towards all CDX2-negative cell lines, xenotransplants, and PDOs. The potential for effective pairing of therapeutic efficacy (IC50) and biomarker (CDX2-low state) is confirmed in PDOs using multivariate analyses. A 50-gene signature of therapeutic response is derived and tested on 9 independent cohorts (~1700 CRCs), revealing the impact of CDX2-reinstatement therapy could translate into a ~50% reduction in the risk of mortality/recurrence.

CONCLUSIONS

Findings not only validate the precision of the ML approach in targeting CSCs, and objectively assess its impact on clinical outcome, but also exemplify the use of ML in yielding clinical directive information for enhancing personalized medicine.

Epidemiology and early screening strategies for colorectal cancer in China

China ranks the first worldwide in the number of new colorectal cancer (CRC) cases and CRC-related deaths. The increasing incidence of early-onset CRC in recent years highlights the challenges related to CRC screening and prevention. High-quality colonoscopy is the universally used gold standard for CRC screening. Risk assessment combined with a two-step screening strategy based on colonoscopy and non-invasive examinations was proven to be highly effective. However, systematic use of well-established risk factors associated with CRC, beyond age, could better identify those who might harbor advanced colorectal neoplasia, improve the diagnostic yield of current screening modalities, and optimize the selection of individuals who might benefit most from preventive strategies. "Personalization" and "Standardization" are the future development directions of CRC screening, from the initiation of screening in those at high risk for CRC to follow-up after treatment, which are the key to ensure the screening efficiency.

Mutation Profile via Next-Generation Sequencing in Patients with Colorectal Adenocarcinoma and Its Clinicopathological Correlation

BACKGROUND/AIMS

Recent studies that reveal the molecular profiles of colorectal carcinomas have demonstrated tumor heterogeneity. Characterization of colorectal carcinoma-specific genomic alterations is essential for developing more successful and targeted treat- ment protocols. Moreover, it is vital in elucidating the pathogenesis and mechanisms of resistance against treatment and predicting prognosis.

MATERIALS AND METHODS

The study included 73 cases diagnosed with colorectal carcinomas and subjected to molecular analysis by the next-generation sequencing. The association between the clinicopathologic parameters and pathogenic mutations detected in 32 genes was evaluated.

RESULTS

Pathogenic mutations were determined in a total of 24 genes. The Cell Division Cycle 27 (CDC27), Kirsten rat sarcoma viral proto-oncogene (KRAS), serine/threonine protein kinase B-raf (BRAF), phosphatase and tensin homolog, breast cancer 2 (BRCA2), and phosphotidylinositol-4,5-biphosphate 3-kinase (PIK3CA) mutations were determined at higher rates, with the adenomatous polypo- sis coli mutation determined at a lower rate than in the literature. There were significant positive correlations between CDC27 and phosphatase and tensin homolog (PTEN), PTEN and BRCA2, and PTEN and adenomatous polyposis coli (APC) concomitant muta- tions, whereas negative correlations were present between BRAF and KRAS. Statistically significant relationships were present between KRAS exon 2 and mucinous morphology, PIK3CA and absence of perineural invasion, BRAF and tumor differentiation/localization, MutS homolog 3 (MSH3) and tumor diameter, and BRCA2 and absence of lymph node metastasis.

CONCLUSION

It is necessary to have a comprehensive database of genomic alterations of colorectal carcinomas to interpret mutations more accurately clinically. There are no studies on the frequency of mutations in colorectal carcinomas in the Turkish population; thus, follow-up and treatment protocols are organized following the European and American databases and guidelines. A comprehensive study of the colorectal carcinoma patients' mutation profile in the Turkish patient cohort by the next-generation sequencing method will help to provide significant therapeutic, prognostic, and predictive data and design more successful treatment and follow-up strategies.

A case of low-grade intestinal-type mucinous neoplasm of the fallopian tube with KRAS exon 2 mutation

Several types of mucinous lesions of the fallopian tube have been reported, including metaplastic and neoplastic lesions, most of which exhibit gastric phenotypes. Here, we report a unique case of a mucinous tumor arising in the right fallopian tube of a 36-year-old female who presented with refractory abdominal pain for approximately one year. Abdominal CT and MRI found a cystic lesion leading to the diagnosis of hematosalpinx, thus right salpingo-oophorectomy and appendectomy were performed. Macroscopic findings included cystic dilatation of the distal portion of the right fallopian tube, filled with gelatinous mucin. Histologically, mucinous columnar cells proliferated in papillary configurations in the cystic region without invasion, resembling low-grade appendiceal mucinous neoplasms. Immunohistochemical analysis revealed that the neoplastic cells expressed CDX-2 and SATB2, but not WT-1, PAX8, ER, PgR, or claudin 18. Sanger sequencing of the mucinous lesion identified a KRAS exon 2 mutation (p.G12A), confirming similar pathologic and genetic characteristics to ovarian mucinous borderline tumors. This rare low grade intestinal-type mucinous tumor indicates the fallopian tube epithelium can give rise to tumors resembling low-grade appendiceal mucinous neoplasms and cause pseudomyxoma peritonei without appendiceal lesions.

High Wnt2 Expression Confers Poor Prognosis in Colorectal Cancer, and Represents a Novel Therapeutic Target in BRAF-Mutated Colorectal Cancer

Background and Objectives: We aimed to investigate the role of Wnt2 expression in colorectal cancer (CRC) prognosis and evaluate its potential as a therapeutic target in BRAF-mutated CRC. Materials and Methods: Exactly 136 samples of formalin-fixed paraffin-embedded CRC tissue specimens were obtained from patients who underwent surgical resection for CRC. The gene mutation status of the samples was detected using fluorescence PCR. Wnt2 expression was detected using immunohistochemistry. Survival curves with high Wnt2 expression and BRAF mutations were compared using the Kaplan-Meier method. A nomogram was constructed to determine the estimated overall survival probability. We also predicted the 3-year and 5-year survival rates for patients with high Wnt2 expression and BRAF mutations. In total, 50 samples of BRAF-mutated CRC were collected and detected Wnt2 expression by immunohistochemistry. The Chi-squared test was used to analyze the association between Wnt2 expression and BRAF-mutated CRC. Results: High Wnt2 expression and BRAF mutations are associated with poor prognosis of CRC. Multivariate survival analyses indicated that high Wnt2 expression and BRAF mutations are significant independent predictors of CRC prognosis. Furthermore, high Wnt2 expression was significantly associated with BRAF-mutated CRC, and Wnt2 may be a potential therapeutic target for BRAF-mutated CRC. Conclusions: High Wnt2 expression confers poor prognosis in colorectal cancer and represents a novel therapeutic target in BRAF-mutated CRC.

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.

Clinicopathological spectrums and prognosis of primary appendiceal adenocarcinoma, goblet cell adenocarcinoma, and low-grade appendiceal mucinous neoplasms

Primary appendiceal adenocarcinoma (APCA), goblet cell adenocarcinoma (GCA), and low/high-grade appendiceal mucinous neoplasms (LAMN/HAMN) are distinct entities with overlapping clinical presentation and histomorphology, leading to diagnostic challenges. We retrospectively reviewed our archived cases between 2010 and 2018 for diagnosis reappraisal and comparative analysis using updated terminology and modern parameters. A total of 87 cases (22 APCA, 40 GCA, and 25 LAMN pT≥3) were included. The entire cohort had 49 women and 38 men with a median age of 59.9 (range 26-88) years. There were no statistically significant differences in age and sex among the three groups. Clinically, patients with GCA were more likely to present with acute appendicitis (65%) and more likely to have appendectomy as initial surgery (68%). Both APCA and GCA were more likely to involve the proximal appendix while LAMN was more likely to involve the distal appendix (p<0.05). All APCAs were associated with mucosal precursor lesions, most commonly tubular, tubulovillous, or villous adenoma, flat LAMN/HAMN-pTis mucinous epithelium, or mixed, which correlated with distinct histomorphology, tumour differentiation, and stage. Although polypoid precursor lesions were rare in GCA, a significant proportion of GCA showed crypt atypia associated with neoplastic cells. Immunohistochemically, APCA had more frequent β-catenin nuclear positivity and loss of SATB2 expression (p<0.05). KRAS mutation was more common in APCA than in GCA (8/11 vs 1/7, p<0.01). We further validated the three-tiered grading system (G1, G2, G3) in GCA, which correlated well with tumour stage and patient survival. APCA had worse progression-free and disease-specific survivals than GCA and LAMN (pT≥3) with the latter being relatively indolent even when perforated with peritoneal spread. Our study is the first comprehensive comparison between all three appendiceal neoplasms. We also describe a spectrum of previously under-recognised crypt atypia in GCA, which should trigger a diligent search for GCA if present.

Identification of a prognostic signature and ENTR1 as a prognostic biomarker for colorectal mucinous adenocarcinoma

Background

Mucinous adenocarcinoma (MAC) is a unique clinicopathological colorectal cancer (CRC) type that has been recognized as a separate entity from non-mucinous adenocarcinoma (NMAC), with distinct clinical, pathologic, and molecular characteristics. We aimed to construct prognostic signatures and identifying candidate biomarkers for patients with MAC.

Methods

Differential expression analysis, weighted correlation network analysis (WGCNA), and least absolute shrinkage and selection operator (LASSO)-Cox regression model were used to identify hub genes and construct a prognostic signature based on RNA sequencing data from TCGA datasets. The Kaplan-Meier survival curve, gene set enrichment analysis (GSEA), cell stemness, and immune infiltration were analyzed. Biomarker expression in MAC and corresponding normal tissues from patients operated in 2020 was validated using immunohistochemistry.

Results

We constructed a prognostic signature based on ten hub genes. Patients in the high-risk group had significantly worse overall survival (OS) than patients in the low-risk group (p < 0.0001). We also found that ENTR1 was closely associated with OS (p = 0.016). ENTR1 expression was significantly positively correlated with cell stemness of MAC (p < 0.0001) and CD8+ T cell infiltration (p = 0.01), whereas it was negatively associated with stromal scores (p = 0.03). Finally, the higher expression of ENTR1 in MAC tissues than in normal tissues was validated.

Conclusion

We established the first MAC prognostic signature, and determined that ENTR1 could serve as a prognostic marker for MAC.

Quantitative Pathologic Analysis of Digitized Images of Colorectal Carcinoma Improves Prediction of Recurrence-Free Survival

BACKGROUND & AIMS

To examine whether quantitative pathologic analysis of digitized hematoxylin and eosin slides of colorectal carcinoma (CRC) correlates with clinicopathologic features, molecular alterations, and prognosis.

METHODS

A quantitative segmentation algorithm (QuantCRC) was applied to 6468 digitized hematoxylin and eosin slides of CRCs. Fifteen parameters were recorded from each image and tested for associations with clinicopathologic features and molecular alterations. A prognostic model was developed to predict recurrence-free survival using data from the internal cohort (n = 1928) and validated on an internal test (n = 483) and external cohort (n = 938).

RESULTS

There were significant differences in QuantCRC according to stage, histologic subtype, grade, venous/lymphatic/perineural invasion, tumor budding, CD8 immunohistochemistry, mismatch repair status, KRAS mutation, BRAF mutation, and CpG methylation. A prognostic model incorporating stage, mismatch repair, and QuantCRC resulted in a Harrell's concordance (c)-index of 0.714 (95% confidence interval [CI], 0.702-0.724) in the internal test and 0.744 (95% CI, 0.741-0.754) in the external cohort. Removing QuantCRC from the model reduced the c-index to 0.679 (95% CI, 0.673-0.694) in the external cohort. Prognostic risk groups were identified, which provided a hazard ratio of 2.24 (95% CI, 1.33-3.87, P = .004) for low vs high-risk stage III CRCs and 2.36 (95% CI, 1.07-5.20, P = .03) for low vs high-risk stage II CRCs, in the external cohort after adjusting for established risk factors. The predicted median 36-month recurrence rate for high-risk stage III CRCs was 32.7% vs 13.4% for low-risk stage III and 15.8% for high-risk stage II vs 5.4% for low-risk stage II CRCs.

CONCLUSIONS

QuantCRC provides a powerful adjunct to routine pathologic reporting of CRC. A prognostic model using QuantCRC improves prediction of recurrence-free survival.

Clinical, Morphologic, and Molecular Features Associated With Ovarian Metastases From Pattern A Endocervical Adenocarcinomas

Ovarian metastases from endocervical adenocarcinomas (EAs) are rare but well-described. Silva Pattern A tumors have been reported to pose essentially no risk of lymph node metastases or recurrence. We describe a cohort of patients with Silva Pattern A EAs with ovarian metastases, as well as involvement of other sites. Eight pattern A EAs with ovarian metastases (4 synchronous, 4 metachronous) were identified from our institution's pathologic archives (2008-2021). Clinicopathologic and molecular features for each case were recorded. All patients were treated by hysterectomy; in each case, the entire tumor was submitted for histologic evaluation. The synchronous metastases were all clinically suspected to be ovarian primary tumors; EAs with metachronous ovarian involvement were confined to the uterus at initial diagnosis, with ovarian metastasis occurring 5 to 171 months after hysterectomy. Morphologically, all tumors were predominantly gland-forming, 5/8 (63%) displayed prominent mucinous differentiation, and 5/8 (63%) involved the corpus. All EAs were either noninvasive (exophytic/papillary/more complex than adenocarcinoma in situ) or showed nondestructive cervical stromal invasion to a depth of 5 mm or less. In the 5 tumors tested by next-generation sequencing, ARID1A, GNAS, and KRAS mutations were detected in 2 (40%), 3 (60%), and 4 (80%) cases, respectively. All 6 patients with follow-up (range, 32 to 181 mo; median, 99.5 mo) had at least 1 recurrence. All but one are without evident disease at last clinical assessment. In an otherwise typical Silva Pattern A EA, corpus involvement, mucinous differentiation, and certain gene mutations may be associated with risk for synchronous or metachronous ovarian metastases.

Mucinous adenocarcinoma: A unique clinicopathological subtype in colorectal cancer

Mucinous adenocarcinoma (MAC) is a unique clinicopathological subtype of colorectal cancer, which is characterized by extracellular mucinous components that comprise at least 50% of the tumor tissue. The clinical characteristics, molecular features, response to chemo-/radiotherapy, and prognosis of MAC are different from that of non-MAC (NMAC). MAC is more common in the proximal colon, with larger volume, higher T-stage, a higher proportion of positive lymph nodes, poorer tumor differentiation, and a higher proportion of peritoneal implants compared to NMAC. Although biopsy is the main diagnostic method for MAC, magnetic resonance imaging is superior in accuracy, especially for rectal carcinoma. The aberrant expression of mucins, including MUC1, MUC2 and MUC5AC, is a notable feature of MAC, which may be related to tumor invasion, metastasis, inhibition of apoptosis, and chemo-/radiotherapy resistance. The genetic origin of MAC is mainly related to BRAF mutation, microsatellite instability, and the CpG island methylator phenotype pathway. In addition, the poor prognosis of rectal MAC has been confirmed by various studies, and that of colonic MAC is still controversial. In this review, we summarize the epidemiology, clinicopathological characteristics, molecular features, methods of diagnosis, and treatments of MAC in order to provide references for further fundamental and clinical research.

Clinical significance of mucinous component in colorectal adenocarcinoma: a propensity score-matched study

Background

This study aims to investigate the clinical significance and prognostic value of mucinous component (MC) in colorectal adenocarcinoma (AC).

Methods

Patients with colorectal AC and AC with MC (ACMC) (1–100%) underwent surgical resection between January 2007 and February 2018 were retrospectively reviewed. Propensity score matching (PSM) was performed according to a 1:1 ratio. Receiver-operating characteristic (ROC) curve was used to identify the optimal cut-off value of MC ratio for prognostic prediction. The clinicopathological features and 3-year overall survival (OS) of AC patients, mucinous adenocarcinoma (MAC) (MC > 50%) patients, and ACMC (1–50%) patients were compared before and after matching. Multivariable analysis was used for analyzing independent risk factors related to prognosis.

Results

A total of 532 patients were enrolled in this study. Patients with AC, MAC, and ACMC (1–50%) exhibited different clinicopathological features. However, their 3-year OS rates were similar (82.00% vs. 74.11% vs. 81.48%, P = 0.38). After matching, ROC curve determined 70% as the optimal cut-off value. And patients with ACMC > 70% had a much poorer 3-year OS compared with ACMC (1–70%) patients and AC patients (47.37% vs. 86.15% vs. 79.76%, P < 0.001). In addition, ACMC > 70% was revealed as a risk factor for poor survival in univariate analysis (HR = 1.643, 95%CI = 1.025–2.635, P = 0.039), though not an independent risk factor in multivariable analysis (HR = 1.550, 95%CI = 0.958–2.507, P = 0.074).

Conclusions

MAC is usually diagnosed at an advanced stage. MAC has a similar survival with AC and ACMC (1–50%) patients before and after matching. Patients with ACMC > 70% exhibited a much poorer OS, and should be given more clinical attention.

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.

Next Generation Sequencing analysis suggests varied multistep mutational pathogenesis for Endocrine Mucin Producing Sweat Gland Carcinoma with comments on INSM1 and MUC2 suggesting a conjunctival origin

Endocrine mucin-producing sweat gland carcinoma (EMPSGC) is a low-grade eyelid tumor. Small biopsies and insensitive immunohistochemistry predispose to misdiagnosis. We aimed to identify clarifying immunohistochemical and/or molecular markers. Clinicopathologic data (22 cases) was reviewed. Immunohistochemistry (Insulinoma-associated protein-1(INSM1), BCL-2, MUC2, MUC4, androgen-receptor, Beta-catenin, MCPyV) and next generation sequencing (MSK-IMPACT, 468 genes) was performed (3 cases). Female (n=15) and male (n=7) patients, mean-age 71.8 years (53-88), had eyelid/periorbital tumors (>90%) with mucin-containing solid/cystic neuroendocrine pathology. Immunohistochemistry (INSM1, BCL2, androgen-receptor, RB1, Beta-catenin) was diffusely-positive (5/5), MUC2 partial, MUC4 focal, and MCPyV negative. MSK-IMPACT identified 12 single-nucleotide-variants and one in-frame deletion in 3 cases, each with DNA damage response/repair (BRD4, PPP4R2, RTEL1) and tumor-suppressor pathway (BRD4, TP53, TSC1, LATS2) mutations. Microsatellite instability, copy number alterations, and structural alterations were absent. INSM1 and MUC2 are positive in EMPSGC. MUC2 positivity suggests conjunctival origin. Multistep pathogenesis involving DNA damage repair and tumor-suppressor pathways may be implicated.