Pathologic Factors Associated with Prognosis after Adjuvant Chemotherapy in Stage II/III Microsatellite-Unstable Colorectal Cancers

Clinicopathological features and evaluation of microsatellite stability of colorectal carcinoma with cribriform comedo pattern

BACKGROUND

Cribriform comedo-type adenocarcinoma (CCA) was a colon cancer subtype defined in the 2009 World Health Organization (WHO) classification. In the 2018 classification, it was a colon cancer subtype included in the adenocarcinoma, Not otherwise specified (NOS) group. A few studies have reported that colon cancers with a cribriform pattern have worse overall survival, and most of them are microsatellite stable (MSS). In this study, we evaluated CCAs based on their clinicopathologic features and microsatellite stability. We aimed to answer whether these tumors could be defined as a distinct morphologic subtype with prognostic significance.

MATERIALS AND METHODS

Pathology reports and specimens from 449 patients with colorectal adenocarcinoma (CRA) were re-evaluated. All subtypes were determined. To evaluate MSS status, the CCA cases were immunohistochemically stained with anti-MLH1, MSH2, MSH6, and PMS2 antibodies.

RESULTS

CCA was present in 40.5% of cases. These cases were found to have higher rates of lymph node metastasis, lymphovascular-perineural invasion, metastasis, and advanced stage ( P < 0.05). Also, 2.7% of CCA cases were microsatellite instable (MSI). However, no statistically significant result was found regarding overall survival and progression-free survival of CCA cases with MSI.

CONCLUSION

According to the findings, CRAs with comedo cribriform patterns are tumors with more aggressive features. It can be said that these tumors have a specific molecular feature related to MSS. Because this feature is important for planning adjuvant chemotherapy, it may be useful to identify cases, particularly with a cribriform comedo pattern >90%. However, because no significant difference in survival rates was found, CCAs may not need to be defined as distinct subtypes.

HSP110 as a Diagnostic but Not a Prognostic Biomarker in Colorectal Cancer With Microsatellite Instability

Determination of microsatellite instability (MSI) using molecular test and deficient mismatch repair (dMMR) using immunohistochemistry (IHC) has major implications on colorectal cancer (CRC) management. The HSP110 T₁₇ microsatellite has been reported to be more monomorphic than the common markers used for MSI determination. Large deletion of HSP110 T₁₇ has been associated with efficacy of adjuvant chemotherapy in dMMR/MSI CRCs. The aim of this study was to evaluate the interest of HSP110 deletion/expression as a diagnostic tool of dMMR/MSI CRCs and a predictive tool of adjuvant chemotherapy efficacy. All patients with MSI CRC classified by molecular testing were included in this multicenter prospective cohort (n = 381). IHC of the 4 MMR proteins was carried out. HSP110 expression was carried out by IHC (n = 343), and the size of HSP110 T₁₇ deletion was determined by PCR (n = 327). In the 293 MSI CRCs with both tests, a strong correlation was found between the expression of HSP110 protein and the size of HSP110 T₁₇ deletion. Only 5.8% of MSI CRCs had no HSP110 T₁₇ deletion (n = 19/327). HSP110 T₁₇ deletion helped to re-classify 4 of the 9 pMMR/MSI discordance cases as pMMR/MSS cases. We did not observe any correlation between HSP110 expression or HSP110 T₁₇ deletion size with time to recurrence in patients with stage II and III CRC, treated with or without adjuvant chemotherapy. HSP110 is neither a robust prognosis marker nor a predictor tool of adjuvant chemotherapy efficacy in dMMR/MSI CRC. However, HSP110 T₁₇ is an interesting marker, which may be combined with the other pentaplex markers to identify discordant cases between MMR IHC and MSI.

Cribriform colon cancer: a morphological growth pattern associated with extramural venous invasion, nodal metastases and microsatellite stability

BACKGROUND

Cribriform comedo-type adenocarcinoma was a colon cancer subtype recognised in the previous WHO classification of tumours that is no longer included in the recent edition. Previous reports have described colon cancers with cribriform growth as having worse overall survival and being associated with microsatellite stability. We sought to validate whether cribriform carcinoma (CC) is a distinct morphological subtype with clinical relevance in the context of modern colon cancer diagnosis.

METHODS

Consecutive cases of non-neoadjuvantly treated colon cancer resections were identified (n=177) and reviewed to evaluate for CC and other histopathological and clinical features. CC was defined as solid nests of cancer with round, 'punched out' spaces and intraluminal bridges, reminiscent of ductal carcinoma in situ of the breast.

RESULTS

CC was present in 18.6% of the consecutive case cohort. Compared with all other cases, CC was associated with positive lymph nodes, increased depth of invasion, extramural venous involvement (EMVI), and microsatellite stability, and was less likely to have tumour infiltrating lymphocytes (p<0.05). In contrast to previous reports, we did not find significantly worse overall, disease-specific or recurrence-free survival for CC. Morphological features mimicking CC occurred in 33.3% of all other colon cancer cases.

CONCLUSION

Identifying CC may be useful due to its association with worse stage at presentation and EMVI, but given that cribriform-like appearance may be found in many colon cancer cases and that we did not find a survival difference for CC, CC may not necessitate its own subtype classification.

Prognostic Predictability of American Joint Committee on Cancer 8th Staging System for Perihilar Cholangiocarcinoma: Limited Improvement Compared with the 7th Staging System

Purpose

This study was conducted to evaluate the prognostic values of the 7th and 8th American Joint Committee on Cancer (AJCC) staging systems for patients with resected perihilar cholangiocarcinoma (PHCC).

Materials and Methods

A total of 348 patients who underwent major hepatectomy for PHCC between 2008 and 2015 were identified from a single center. Overall survival (OS) was estimated using the Kaplan-Meier method and compared across stage groups with the log-rank test. The concordance index was used to evaluate the prognostic predictability of the 8th AJCC staging system compared with that of the 7th.

Results

In the 8th edition, the stratification of each group of T classification improved compared to that in the 7th, as the survival rate of T4 decreased (T2, 31.2%; T3, 13.9%; T4, 15.1%; T1-T2, p=0.260; T2-T3, p=0.001; T3-T4, p=0.996). Both editions showed significant survival differences between each N category, except between N1 and N2 (p=0.063) in 7th edition. Differences of point estimates between the 8th and 7th T and N classification and overall stages were +0.028, +0.006, and +0.039, respectively (T, p=0.005; N, p=0.115; overall stage, p=0.005). In multivariable analysis, posthepatectomy liver failure, T category, N category, distant metastasis, histologic differentiation, intraoperative transfusion, and resection margin status were associated with OS.

Conclusion

The prognostic predictability of 8th AJCC staging for PHCC improved slightly, with statistical significance, compared to the 7th edition, but its overall performance is still unsatisfactory.

On cribriform prostate cancer

The management of newly diagnosed prostate cancer is challenging because of its heterogeneity in histology, genetics and clinical outcome. The clinical outcome of patients with Gleason score 7 prostate cancer varies greatly. Improving risk assessment in this group is of particular interest, as Gleason score 7 prostate cancer on biopsy is an important clinical threshold for active treatment. Architecturally, four Gleason grade 4 growth patterns are recognized: ill-formed, fused, glomeruloid and cribriform. The aim of this review is to describe the role of cribriform growth in prostate cancer with respect to diagnosis, prognosis and molecular pathology. Secondly, we will discuss clinical applications for cribriform prostate cancer and give recommendations for future research.

Distinct features between MLH1-methylated and unmethylated colorectal carcinomas with the CpG island methylator phenotype: implications in the serrated neoplasia pathway

The presence or absence of MLH1 methylation may critically affect the heterogeneity of colorectal carcinoma (CRC) with the CpG island methylator phenotype (CIMP). Here, we investigated the differential characteristics of CIMP-high (CIMP-H) CRCs according to MLH1 methylation status. To further confirm the MLH1-dependent features in CIMP-H CRC, an independent analysis was performed using data from The Cancer Genome Atlas (TCGA). In our CIMP-H CRC samples, MLH1-methylated tumors were characterized by older patient age, proximal colonic location, mucinous histology, intense lymphoid reactions, RUNX3/SOCS1 promoter methylation, BRAF mutations, and microsatellite instability-high (MSI-H) status. By contrast, MLH1-unmethylated tumors were associated with earlier age of onset, increased distal colorectal localization, adverse pathologic features, and KRAS mutations. In the TCGA dataset, the MLH1-silenced CIMP-H CRC demonstrated proximal location, MSI-H status, hypermutated phenotype, and frequent BRAF mutations, but the MLH1-non-silenced CIMP-H CRC was significantly associated with high frequencies of KRAS and APC mutations. In conclusion, the differential nature of CIMP-H CRCs depends primarily on the MLH1 methylation status. Based on the current knowledge, the sessile serrated adenoma/polyp may be the major precursor of MLH1-methylated CIMP-H CRCs, whereas MLH1-unmethylated CIMP-H CRCs may develop predominantly from KRAS-mutated traditional serrated adenomas and less commonly from BRAF-mutated traditional serrated adenomas and/or sessile serrated adenomas/polyps.

Prognostic predictability of the new American Joint Committee on Cancer 8th staging system for distal bile duct cancer: limited usefulness compared with the 7th staging system

BACKGROUND

The new 8th American Joint Committee on Cancer (AJCC) staging has recently been released and there are major changes in distal bile duct (DBD) cancer staging. However, clinical validation is needed before the changes can be widely implemented.

METHODS

This study was performed to evaluate the prognostic predictability of the 8th AJCC staging compared with that of the 7th using C statistics.

RESULTS

A total of 293 consecutive patients who had curative-intended surgery were enrolled. There was no significant difference of the 5-year survival rate between 7th T1 and T2 (P = 0.123), but significant difference between T2 and T3 (P = 0.039). There were significant differences in pairwise comparisons between the 8th T stage (T1 vs. T2, P = 0.001; T2 vs. T3, P = 0.014). The number of regional lymph node metastases also showed prognostic predictability. The 8th T and N stage both showed comparable prognostic predictability with the 7th (95% confidential intervals for C; T, -0.043 -0.097, N, -0.001 - 0.008).

CONCLUSIONS

The 8th AJCC staging for DBD cancer does not have better prognostic predictability than the 7th stage does. The previous pathologic results would become useless unless they were reviewed entirely. Therefore, introduction of the AJCC 8th staging has to be reconsidered, especially for new T staging.

Dominant high expression of wild-type HSP110 defines a poor prognostic subgroup of colorectal carcinomas with microsatellite instability: a whole-section immunohistochemical analysis

The aim of this study is to establish heat shock protein 110 (HSP110) as a prognostic biomarker of colorectal carcinomas (CRCs) with microsatellite instability-high (MSI-H) by considering the intratumoral heterogeneity of HSP110 expression. We performed whole-section immunohistochemistry (IHC) for wild-type HSP110 (HSP110wt) in 164 MSI-H CRCs. The intensity of the HSP110wt expression in tumor cells was semiquantitatively scored (0/1/2/3), and the HSP110wt expression status of each tumor was classified as low or high using the following four scoring criteria: H-score, dominant intensity score, lowest intensity score, and highest intensity score. Among the four criteria, only the dominant intensity score-based dichotomous classification of HSP110wt expression was significantly associated with a difference in disease-free survival (log-rank p = 0.035) in 164 MSI-H CRCs. The HSP110wt-low MSI-H CRCs were significantly correlated with larger deletions in the HSP110 T₁₇ mononucleotide repeat (≥4 bp; p < 0.001). In conclusion, the dominant intensity score-based assessment of HSP110wt IHC can be a simple and useful method for the prognostic stratification of MSI-H CRCs. It is expected that HSP110wt IHC may be used to identify a subgroup of MSI-H CRCs with poor prognosis and/or candidates for further treatment, such as immunotherapy using immune checkpoint inhibitors in MSI-H CRCs.

Intratumoral Fusobacterium nucleatum abundance correlates with macrophage infiltration and CDKN2A methylation in microsatellite-unstable colorectal carcinoma

Fusobacterium nucleatum (Fn), a specific species of gut microbiota, has been suggested to be enriched in the microsatellite instability-high (MSI-H) molecular subtype of colorectal carcinomas (CRCs). However, the clinicopathologic and molecular factors that interact with Fn in MSI-H CRCs are poorly understood. In this study, 16S ribosomal RNA gene DNA sequence of Fn was quantitatively measured by real-time polymerase chain reaction in tumor DNA samples from a total of 160 surgically resected MSI-H CRC tissues. Each case was classified into one of the three categories based on the Fn DNA amount: Fn-high, Fn-low, and Fn-negative. The clinicopathologic and molecular associations of Fn in MSI-H CRCs were statistically analyzed. Among the 160 MSI-H CRC samples, 15 (9%), 92 (58%), and 53 (33%) cases were Fn-high, Fn-low, and Fn-negative, respectively. Compared with Fn-low/negative tumors, Fn-high MSI-H CRCs were significantly associated with a high density of CD68+ tumor-infiltrating macrophages (P = 0.019) and promoter CpG island hypermethylation of the CDKN2A (p16) gene (P = 0.008). There were also tendencies toward associations of Fn-high with the BRAF V600E mutation (P = 0.047) and active Crohn-like lymphoid reactions (P = 0.052) in MSI-H CRCs. However, Fn-high was not significantly associated with CD3+ T cell density, CD163+ M2 macrophage density or PD-L1 expression status. In conclusion, high amounts of intratumoral Fn are correlated with increased macrophage infiltration and CDKN2A promoter methylation in MSI-H CRCs.

An Updated Review of Cribriform Carcinomas with Emphasis on Histopathological Diagnosis and Prognostic Significance

Cribriform is a histopathological term used to describe a neoplastic epithelial proliferation in the form of large nests perforated by many quite rounded different-sized spaces. This growth pattern may be seen in carcinomas arising in different organs, and shows important prognostic implications. Therefore, recent data in literature suggest that cribriform carcinoma is a histologically and clinically distinctive type of tumour that should be separated from other similar tumour types. In this article, the pathology of cribriform adenocarcinoma of the prostate, lung, breast, stomach, colon, thyroid, and skin is discussed with particular reference to morphologic and immunohistochemical features, differential diagnosis, and clinical behaviour.

Tumor deposits: markers of poor prognosis in patients with locally advanced rectal cancer following neoadjuvant chemoradiotherapy

Background

Tumor deposits (TDs) were reported to be poor prognoses in colorectal carcinoma, but the significance in locally advanced rectal cancer (LARC) (T3-4/N+) following neoadjuvant chemoradiotherapy (neo-CRT) and surgery is unclear. Since adjuvant chemotherapy showed no benefit for LARC following neo-CRT, it is of great value to investigate whether TDs can identify the subgroup of patients who may benefit from adjuvant chemotherapy.

Methods

Between 2004 and 2012, 310 LARC patients following neo-CRT and surgery were retrospectively reviewed. Overall survival (OS), disease-free survival (DFS), distant metastasis free survival (DMFS) and local recurrence free survival (LRFS) were evaluated by Kaplan-Meier method, log-rank test and Cox models.

Results

TDs-positive patients showed adverse OS, DFS and DMFS (all P≤0.001), but not LRFS (P = 0.273). In multivariate analysis, TDs continued to be associated with poor OS (HR = 2.44, 95% CI 1.32-4.4, P = 0.004) and DFS (HR = 1.99, 95% CI 1.21-3.27, P = 0.007), but not DMFS (HR = 1.77, 95% CI 0.97-3.20, P = 0.061) or LRFS (HR = 1.85, 95% CI 0.58-5.85, P = 0.298). Among TDs-positive patients, adjuvant chemotherapy significantly improved OS (P = 0.045) and DMFS (P = 0.026), but not DFS (P = 0.127) or LRFS (P = 0.862).

Conclusions

TDs are predictive of poor survival in LARC after neo-CRT. Fortunately, TDs-positive patients appear to benefit from adjuvant chemotherapy.

BRAF-Mutated Colorectal Cancer Exhibits Distinct Clinicopathological Features from Wild-Type BRAF-Expressing Cancer Independent of the Microsatellite Instability Status

In patients with colorectal cancer (CRC), the BRAF V600E mutation has been reported to be associated with several clinicopathological features and poor survival. However, the prognostic implications of BRAF V600E mutation and the associated clinicopathological characteristics in CRCs remain controversial. Therefore, we reviewed various clinicopathological features, including BRAF status, in 349 primary CRCs and analyzed the relationship between BRAF status and various clinicopathological factors, including overall survival. Similar to previous studies conducted in Eastern countries, the incidence of the BRAF V600E mutation in the current study was relatively low (5.7%). BRAF-mutated CRC exhibits distinct clinicopathological features from wild-type BRAF-expressing cancer independent of the microsatellite instability (MSI) status. This mutation was significantly associated with a proximal tumor location (P = 0.002); mucinous, signet ring cell, and serrated tumor components (P < 0.001, P = 0.003, and P = 0.008, respectively); lymphovascular invasion (P = 0.004); a peritumoral lymphoid reaction (P = 0.009); tumor budding (P = 0.046); and peritoneal seeding (P = 0.012). In conclusion, the incidence of the BRAF V600E mutation was relatively low in this study. BRAF-mutated CRCs exhibited some clinicopathological features which were also frequently observed in MSI-H CRCs, such as a proximal location; mucinous, signet ring cell, and serrated components; and marked peritumoral lymphoid reactions.

Characterisation of PD-L1-positive subsets of microsatellite-unstable colorectal cancers

Background:

The aim of this study was to reveal the clinicopathological and molecular characteristics of microsatellite instability-high (MSI-H) colorectal cancers (CRCs) showing programmed death ligand-1 (PD-L1) positivity, which are good candidates for anti-PD-1/PD-L1 immunotherapy.

Methods:

The PD-L1 expression status of 208 MSI-H CRCs was retrospectively analysed using immunohistochemistry. PD-L1 positivity in tumour cells (PD-L1+(T)) and PD-L1 positivity in immune cells (PD-L1+(I)) were separately evaluated.

Results:

Programmed death ligand-1 positivity in tumour cells and PD-L1+(I) were observed in 26 (12.5%) and 62 (29.8%) MSI-H CRCs, respectively, and occasionally overlapped (n=12; 5.8%). Programmed death ligand-1 positivity tumours in MSI-H CRCs were significantly associated with older age, female sex, non-mucinous-type poor differentiation, infiltrating growth, tumour budding, advanced stage, CpG island methylator phenotype-high, MLH1 promoter methylation, and BRAF V600E mutations. However, PD-L1+(I) MSI-H CRCs were characterised by high-density tumour-infiltrating immune cells, including T cells and macrophages, and intense peritumoural lymphoid reactions. In patients with stage IV MSI-H CRCs who had undergone metastatectomy (n=4), the PD-L1 status of primary tumours was maintained in corresponding distant metastatic lesions.

Conclusions:

In MSI-H CRCs, PD-L1+(T) and PD-L1+(I) are linked to a sporadic hypermethylated subtype and an immune cell-rich subtype, respectively. Potential differential therapeutic implications of PD-L1+(T) and PD-L1+(I) in CRCs should be further investigated.

TNM Staging of Colorectal Cancer Should be Reconsidered According to Weighting of the T Stage: Verification Based on a 25-Year Follow-Up

The gradient monotonicity of existing tumor, node, metastases staging systems for colorectal cancer is unsatisfactory. Our proposed T-plus staging system strengthens weighting of the T stage. In this study, applicability of the T-plus staging system was verified with data of a Chinese colorectal cancer center.Records of 2080 nonmetastatic, advanced cancer patients undergoing colorectal cancer surgery from 1985 to 2011 were reviewed for T, N stage pathology and follow-up information. Using overall and disease-specific survival data, the 7th edition tumor, node, metastases staging system and the T-plus staging system were compared for stage homogeneity and discrimination and gradient monotonicity.For gradient monotonicity, the T-plus staging system was superior for both colon and rectal cancer. With Kaplan-Meier survival curves, the T-plus staging system discriminated among different stages, and the corresponding survival was inversely associated with the stage. However, for the 7th edition tumor, node, metastases staging system, stage IIIa had a better prognosis than stage II for rectal cancer and stage I for colon cancer. For homogeneity within the same stage and discrimination between different stages, the 2 staging systems were similar for colorectal cancer, but the T-plus system was clearly better for colon cancer.The T-plus staging system provides good gradient monotonicity. For future colorectal cancer staging systems, we propose replacement of lymph node status as the criterion to discriminate colorectal cancer stage II and stage III with greater weighting of the T stage.