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

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

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

Clinical, Pathologic, Genetics and Intratumoral Immune Milieu of Serrated Adenocarcinoma of the Colon

BACKGROUND

Serrated adenocarcinoma (SAC), a recognized WHO variant of colonic adenocarcinoma, is the purported end-product of serrated neoplasia. Yet, the diagnosis of SAC is infrequently rendered, and little is known about its prognosis, immune microenvironment, and molecular alterations.

MATERIALS AND METHODS

We assessed 903 consecutive colon carcinomas and recognized tumors with ≥5% (n=77) serrated pattern, and ≥50% serrated pattern (n=13). We assessed precursor polyps and synchronous polyps. We recorded demographic/clinical parameters, histological features, and MMR status. We performed immunohistochemistry and quantification on tissue microarray for HLA class I/II proteins, beta-2-microglobulin (B2MG), CD8, CD163, LAG3, PD-L1, FoxP3, PD-L1and BRAF V600E.

RESULTS

We identified ≥ 5% epithelial serration prevalence in 8.5% of cases, and ≥50% epithelial serration prevalence in 1.4% of cases. Precursor lesions were present in 21.4% of cases; these were mostly tubular adenomas with two traditional serrated adenoma identified. SAC with ≥ 5% serrations exhibited lower numbers of CD8 positive lymphocytes (p=0.002) and lower B2MG expression (p=0.048), although neither value was significant at ≥50% serration threshold. There was no difference in HLA class I/II, or PD-L1 expression on tumor cells and no difference in PD-L1, LAG3, FOXP3 and CD163 expression on immune cells. There was no association with MMR status, or BRAFV600E relative to conventional adenocarcinoma. There was improved disease-specific survival on univariate (but not multivariate) analysis between carcinomas with serrated pattern and non-mucinous conventional colonic carcinomas at ≥5% epithelial serrations (p=0.04).

CONCLUSION

SAC category shows a limited impact on survival, and this phenotype may harbor a unique immunologic milieu.

Clinicopathological Features and Survival of Signet-Ring Cell Carcinoma and Mucinous Adenocarcinoma of Right Colon, Left Colon, and Rectum

Histological subtype plays an important role in the different clinical characteristics and survival outcomes of patients with colorectal carcinoma (CRC). However, in previous studies, the influences of tumor locations and tumor stages have not been strictly controlled. This study focused on the assessment of the prognostic value of each histological subtype in different tumor locations and tumor stages of CRC. We used the Surveillance, Epidemiology, and End Results (SEER) database (1973-2011) to analyze 818,229 CRC patients with different clinical and pathological features, and analyzed the prognostic value of each histological subtype. Under the condition of stratification by tumor stage, signet-ring cell carcinoma (SRCC) presented the worst survival in each stage of right colon cancer (stage I, log-rank, p = 0.002, stages II, III, and IV, log-rank, p < 0.001), rectal cancer (RC) (log-rank, p < 0.001), and in stages II, III, and IV of left colon cancer (log-rank, p < 0.001). Multivariate survival analysis suggested SRCC subtype, male gender, age ≥ 70 years, tumor size ≥ 5 cm, stage progression, and poor differentiation were all significant factors worsening survival in CRC (p < 0.001, respectively). Mucinous adenocarcinoma (MC) histological subtype proved to be an independent protective factor for the prognosis of right colon cancer (p = 0.003). Overall, in our study, the results suggested SRCC had the worst survival among the three histological subtypes of CRC. MC was associated with favorable prognosis in right colon cancer but not with other tumor locations.

Clinicopathological features of mismatch repair protein expression patterns in colorectal cancer

Microsatellite instability (MSI) is reflective of a deficient mismatch repair (dMMR) system, which is mostly associated with the methylation of mismatch repair (MMR) genes and BRAF mutations in sporadic colorectal cancers (CRCs). We performed a retrospective study to analyze the clinicopathological features of dMMR CRCs and their association with the BRAF V600E mutation. The incidence of dMMR CRCs in our cohort was 7.4 % (118/1603). Immunohistochemistry (IHC) revealed four common dMMR IHC patterns in 116 dMMR CRCs from 110 patients. dMMR type 1 (MLH1-/PMS2-) CRCs were the most frequent pattern, usually showing typical proximal location and MSI histology. The BRAF V600E mutation was almost exclusively observed in dMMR type 1 (32 of 72) and dMMR type 2 (PMS- only, 7 of 18) CRCs (p = 0.001). Patients with dMMR type 3 (MSH2-/MSH6-) CRCs were usually diagnosed at younger ages (p < 0.001) and had the strongest family history of Lynch syndrome-associated tumors (p = 0.002). dMMR type 3 CRCs frequently presented at advanced stages (p = 0.005) with perineural invasion (p = 0.021). We also found a significant positive association of dMMR type 1 and type 3 with advanced stages of CRC, whereas dMMR types 2 and 4 (MSH6- only) were usually diagnosed at early stages of CRC (p < 0.001). In conclusion, BRAF V600E mutations almost exclusively occurred in dMMR type 1 and 2 CRCs. Patterns of MMR protein expression display distinct associations with tumor staging and age at diagnosis.

Neoplastic meningitis due to colorectal cancer

Herein, we describe a rare case of neoplastic meningitis in a 54-year-old male with a history of colorectal cancer. He first noticed a loss of sensation in his left thigh along with back pain. Magnetic resonance imaging showed a tumor lesion in the cauda equina. The tumor was surgically resected and pathologically diagnosed as a metastatic tumor of the descending colon cancer for which he had undergone resection a year earlier. The patient was treated with chemotherapy using capecitabine, oxaliplatin, and cetuximab. During chemotherapy, his tumor markers decreased and magnetic resonance imaging showed tumor shrinkage, but he became aware of neurological symptoms such as hearing loss, tinnitus, and headache. The patient's condition suddenly worsened during the 5th course of chemotherapy and he died 5 months after the diagnosis. Neoplastic meningitis occurs in 4-15% of patients with solid tumors, but it is rarely seen in colorectal cancer. It should be considered when a patient with a history of cancer has back pain or neurological symptoms. The progression of neoplastic meningitis is fast and it has a poor prognosis. Diagnosis in the early stages is important to prevent progression of neurological symptoms and to provide the most effective treatment.

Expression of the Serrated Markers Annexin A10 or Gremlin1 in Colonic Adenocarcinomas: Morphology and Prognostic Values

Describe clinical, histological and molecular charatcteristics and prognosis values of the serrated candidate markers AnnexinA10 and Gremlin1 in colon adenocarcinomas. Immunohistochemical expression of AnnexinA10 and Gremlin1 was evaluated on 346 colonic adenocarcinomas. Clinicopathological, molecular features and prognostic characteristics were then evaluated. A total of 40 colonic adenocarcinomas expressed AnnexinA10 (11.6%) and, 115 expressed Gremlin1 (40.4%). AnnexinA10 expression was significantly associated, on univariate analyses, with female gender (p = 0.03), right tumor location (p < 0.001), differentiation grade 3 (p < 0.001), serrated adenocarcinoma subtype (p < 0.001), serrated (p < 0.001), medullary (p = 0.005), and mucinous component (p = 0.004), cytoplasmic eosinophilia (p < 0.001), discernible nuclei (p = 0.001), preserved polarity (p < 0.001), lymphatic invasion (p = 0.01), BRAFV600E mutation (p < 0.001), MSI-H status (p < 0.001) and CIMP-H status (p = 0.019). Multivariate analyses revealed that mucinous component (p = 0.002), lymphatic invasion (p = 0.02) and BRAFV600E mutation (p < 0.001) were independently associated with AnnexinA10 expression. In addition, AnnexinA10 was an indicator of poorer overall survival (OS) in UICC stage IV adenocarcinomas (p = 0.01) only. Gremlin1 expression was neither associated with serrated adenocarcinoma subtype (p = 0.51) nor with AnnexinA10 expression (p = 0,31), but was significantly associated, in univariate analysis with male gender (p = 0.002), younger age (p = 0.002), left tumor location (p = 0.04), and MSS status (p = 0.03). Gremlin1 expression was associated with better OS only in UICC stage III colon adenocarcinomas (p = 0.006). Colon adenocarcinomas expressing AnnexinA10 have distinct clinico-pathological and molecular features. AnnexinA10 expression is an indicator of poorer OS in UICC stage IV patients. Gremlin1 expression is not associated with serrated adenocarcinomas subtype. Its expression was associated with better OS in UICC Stage III patients.

Histology and its prognostic effect on KRAS-mutated colorectal carcinomas in Korea

KRAS mutation is frequently identified in advanced colorectal carcinoma (CRC); however, its prognostic significance and the associated histological features have remained to be clarified. In the present study, the precise histological results and prognostic value of KRAS-mutated CRCs were investigated in patients from South Korea. A retrospective review of the results from KRAS mutation testing, as well as evaluation of the histology of 310 cases of CRC at various stages, were performed. Cross-tabulation and survival analysis were performed according to the KRAS status. Patients with KRAS mutation more frequently exhibited serrated and papillary architectures (P=0.009 and P=0.014, respectively). KRAS mutation was an independent unfavorable prognostic factor for overall survival (OS) according to multivariate analysis (P=0.001), whereas no association was observed with disease-free survival (DFS) (P=0.611). Of note, in the subgroup of KRAS-mutated carcinomas, the presence of a solid component on histology was associated with less favorable OS (P=0.032). Furthermore, among the wild type cases, patients with a micropapillary component had a worse OS than those who did not (P=0.018). However, no subgroup or specific histological features were associated with DFS. In summary, KRAS-mutated CRCs had a moderate association with particular histological features, and according to the KRAS mutational status, there was a certain degree of association between histology and prognosis.

Preoperative Neutrophil-Lymphocyte Ratio, Platelet-Lymphocyte Ratio and Lymphocyte-Monocyte Ratio in Peripheral Blood of Patients with Gastrointestinal Malignant Lesions

Local inflammation plays a very important role in the apparition and development of tumors and metastasis. The objective of this study was to investigate the significance of neutrophil to lymphocyte ratio (NLR), lymphocyte to monocyte ratio (LMR) and platelet to lymphocyte ratio (PLR) in peripheral blood of patients with gastrointestinal malignant tumors. Methods: Medical records of 145 patients diagnosed with gastrointestinal malignant tumor between January 2017 and December 2017 were analyzed retrospectively. Pretreatment neutrophil, lymphocyte, platelet and monocyte counts and NLR, LMR and PLR were investigated. Results: The mean for NLR, PLR and LMR in patients with gastrointestinal cancer were determined. Conclusions: Determination of NLR, PLR and LMR can be easily done with a simple blood test and may be useful inflammatory markers as in our study we have observed the presence of increased inflammatory response in patients with gastrointestinal cancer.

Global differences in the prevalence of the CpG island methylator phenotype of colorectal cancer

Background

CpG Island Methylator Phenotype (CIMP) is an epigenetic phenotype in CRC characterized by hypermethylation of CpG islands in promoter regions of tumor suppressor genes, leading to their transcriptional silencing and loss of function. While the prevalence of CRC differs across geographical regions, no studies have compared prevalence of CIMP-High phenotype across regions. The purpose of this project was to compare the prevalence of CIMP across geographical regions after adjusting for variations in methodologies to measure CIMP in a meta-analysis.

Methods

We searched PubMed, Medline, and Embase for articles focusing on CIMP published from 2000 to 2018. Two reviewers independently identified 111 articles to be included in final meta-analysis. We classified methods used to quantify CIMP into 4 categories: a) Classical (MINT marker) Panel group b) Weisenberg-Ogino (W-O) group c) Human Methylation Arrays group and d) Miscellaneous group. We compared the prevalence of CIMP across geographical regions after correcting for methodological variations using meta-regression techniques.

Results

The pooled prevalence of CIMP-High across all studies was 22% (95% confidence interval:21–24%; I² = 94.75%). Pooled prevalence of CIMP-H across Asia, Australia, Europe, North America and South America was 22, 21, 21, 27 and 25%, respectively. Meta-regression analysis identified no significant differences in the prevalence of CIMP-H across geographical regions after correction for methodological variations. In exploratory analysis, we observed variations in CIMP-H prevalence across countries.

Conclusion

Although no differences were found for CIMP-H prevalence across countries, further studies are needed to compare the influence of demographic, lifestyle and environmental factors in relation to the prevalence of CIMP across geographical regions.

Mutations of key driver genes in colorectal cancer progression and metastasis

The association between mutations of key driver genes and colorectal cancer (CRC) metastasis has been investigated by many studies. However, the results of these studies have been contradictory. Here, we perform a comprehensive analysis to screen key driver genes from the TCGA database and validate the roles of these mutations in CRC metastasis. Using bioinformatics analysis, we identified six key driver genes, namely APC, KRAS, BRAF, PIK3CA, SMAD4 and p53. Through a systematic search, 120 articles published by November 30, 2017, were included, which all showed roles for these gene mutations in CRC metastasis. A meta-analysis showed that KRAS mutations (combined OR 1.18, 95% CI 1.05-1.33) and p53 mutations (combined OR 1.49, 95% CI 1.23-1.80) were associated with CRC metastasis, including lymphatic and distant metastases. Moreover, CRC patients with a KRAS mutation (combined OR 1.29, 95% CI 1.13-1.47), p53 mutation (combined OR 1.35, 95% CI 1.06-1.72) or SMAD4 mutation (combined OR 2.04, 95% CI 1.41-2.95) were at a higher risk of distant metastasis. Subgroup analysis stratified by ethnic populations indicated that the BRAF mutation was related to CRC metastasis (combined OR 1.42, 95% CI 1.18-1.71) and distant metastasis (combined OR 1.51, 95% CI 1.20-1.91) in an Asian population. No significant association was found between mutations of APC or PIK3CA and CRC metastasis. In conclusion, mutations of KRAS, p53, SMAD4 and BRAF play significant roles in CRC metastasis and may be both potential biomarkers of CRC metastasis as well as therapeutic targets.

Early-stage serrated adenocarcinomas are divided into several molecularly distinct subtypes

Serrated adenocarcinoma (SAC) is considered the end stage of the serrated neoplasia pathway. Although SAC prognosis is not widely recognized, the serrated pathway-associated subtype consistently exhibits unfavorable prognosis in genetic studies. Herein, we classified molecularly distinct subtypes of serrated adenocarcinomas and clarified their associated clinicopathological characteristics and genetic changes. We examined 38 early-stage colorectal SACs. Of these, 24 were classified into three molecularly distinct groups by colon cancer subtyping (CCS). The clinicopathological characteristics, Ki 67 labeling index (LI), and SAC epithelial serration were assessed. The DNA from carcinomas and normal tissue/adenoma was extracted by laser microdissection and sequenced by next-generation sequencing, and mutation numbers and patterns of a 15-oncogene panel were determined. The CCS groups included CCS1 (CDX2+, HTR2B-, FRMD6-, ZEB1-, and microsatellite instable-low [MSI-L]/microsatellite stable [MSS]; 14 cases), CCS2 (microsatellite instable-high [MSI-H], 5 cases), and CCS3 (CDX2-, HTR2B+, FRMD6+, ZEB1+, and MSI-L/MSS; 5 cases). Invasive cancer was significantly more frequent in CCS3 than in CCS1 (5/5 versus 3/14, respectively). Ki67 LI and epithelial serration were higher in CCS3 than in CCS1 (83.0 ± 5.8 versus 65.4 ± 4.0 and 5/5 versus 3/14, respectively; p = 0.031 and 0.0048). CCS2 showed the highest mutation number, whereas KRAS and BRAF mutation numbers were higher in CCS3 than in CCS1. Early-stage SACs were classified into three molecularly distinct subtypes with different clinicopathological and genetic characteristics.

Advanced Mucinous Colorectal Cancer: Epidemiology, Prognosis and Efficacy of Chemotherapeutic Treatment

BACKGROUND

The clinicopathological significance of the mucinous subtype of colorectal cancer (CRC) remains controversial. As of today, none of the current guidelines differentiate treatment with respect to mucinous or nonmucinous cancer. Due to the lack of substantiated data, best treatment remains unclear and the mucinous subtype of CRC is usually treated along the lines of recommendations for adenocarcinoma of the colon.

METHODS

We investigated an East-Bavarian cohort of 8,758 patients with CRC. These included 613 (7.0%) patients with a mucinous subtype, who were analyzed for assessing their characteristics in clinical course and for evaluating the efficacy of common chemotherapy protocols.

RESULTS AND CONCLUSION

Mucinous CRC was predominantly located in the right hemicolon; it was diagnosed at more advanced stages and occurred with preponderance in women. A higher rate of G3/4 grading was observed at diagnosis (all p < 0.001). An association of mucinous CRC with younger age at initial diagnosis, previously reported by other groups, could not be confirmed. Patients with mucinous stage IV colon cancer demonstrated poorer survival (p = 0.006). In contrast, no differences in survival were observed for specific stages I-III colon cancer. Stage-dependent analysis of rectal cancer stages I-IV also showed no differences in survival. However, univariable overall analysis resulted in significant poorer survival of mucinous compared to nonmucinous rectal cancer (p = 0.029). Also, combined analysis of all patients with mucinous CRC revealed poorer overall survival (OS) of these patients compared to nonmucinous CRC patients (median 48.4 vs. 60.2 months, p = 0.049) but not in multivariable analysis (p = 0.089). Chemotherapeutic treatment showed comparable efficacy regarding OS for mucinous and nonmucinous cancers in both an adjuvant and palliative setting for colon cancer patients (p values comparing mucinous and nonmucinous cancers < 0.001-0.005).

The low prevalence of colonic serrated adenocarcinoma with high KRAS mutational status at Cipto Mangunkusumo Hospital, Indonesia

Background: Serrated adenocarcinoma (SA), a subtype of colorectal carcinoma, and the KRAS mutation, a strong marker for the patient’s response to anti-epidermal growth factor receptor therapy, have a clinical importance because of its progressive nature and tendency for chemoresistance. The purposes of this study were to (1) determine the prevalence of SA, (2) evaluate the histomorphological characteristics of SA and classical adenocarcinoma based on its prognostic factors, (3) determine the prevalence of the KRAS mutation in SA cases, and (4) identify the main characteristics of SA cases and classical adenocarcinoma with a KRAS mutation.Methods: This study was conducted by reviewing hematoxylin-eosin-stained slides of colorectal carcinoma (CRC) cases from January 2013 to July 2015 at the Department of Anatomical Pathology Cipto Mangunkusumo General Hospital. The final diagnosis of SA was based on the Tuppurainen et al criteria and the KRAS mutation was evaluated using real-time polymerase chain reaction.Results: Among the 117 adenocarcinoma cases, there were 41 unequivocal SA, 11 equivocal SA, and 65 classical adenocarcinoma. The prevalence rates of unequivocal and equivocal SA among all CRC cases were 7.7% and 2.1%, respectively. There were 11 (28.2%) cases of wild-type KRAS and 28 (71.7%) cases of mutated KRAS among all unequivocal SA cases. Tumor budding (TB) was the predominant prognostic factor.Conclusion: The prevalence of SA among all CRC cases was 7.7%. The KRAS mutation was found in almost three-quarters of all SA cases.