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.

Micropapillary Structures in Colorectal Cancer: An Anoikis-resistant Subpopulation

BACKGROUND/AIM

Micropapillary structures (MIPs) are focal piles of columnar cells without extracellular matrix contact, and common in serrated colorectal carcinoma (CRC). In order to characterize biology of MIPs in colorectal cancer (CRC), the proliferation and apoptosis rates, and survivin expression were compared between MIPs and other cancer epithelial cells of CRC (non-MIPs).

MATERIALS AND METHODS

We assessed 46 samples of normal colorectal mucosa, 62 carcinomas and 54 polyps for proliferation (Ki67), apoptosis (M30), and survivin expression by immunohistochemistry.

RESULTS

MIPs in carcinoma showed lower rates of proliferation and apoptosis than non-MIPs. A low rate of apotosis in MIPs was associated with poor prognosis in local carcinoma. In normal crypts, nuclear-to-cytoplasmic transition of survivin indicated epithelial cell maturation. Cancer cases showed increased cytoplasmic expression of survivin than normal mucosa and polyps. However, MIPs showed lower nuclear and cytoplasmic survivin expression than non-MIPs. Our findings suggest that MIPs represent a biologically distinct subpopulation of carcinoma cells with features of anoikis resistance and possibly quiescence.

Clinicopathologic and endoscopic features of early-stage colorectal serrated adenocarcinoma

Background

Serrated adenocarcinoma (SAC) is a distinct colorectal carcinoma variant that accounts for approximately 7.5% of all advanced colorectal carcinomas. While its prognosis is worse than conventional carcinoma, its early-stage clinicopathologic features are unclear. We therefore aimed to clarify the clinicopathologic and endoscopic characteristics of early-stage SACs.

Methods

Forty consecutive early-stage SAC patients at Hiroshima University Hospital were enrolled; SACs were classified into epithelial serration (Group A, n = 17) and non-epithelial serration (Group B, n = 23) groups. Additionally, we classified serrated adenoma into 4 types: sessile serrated adenoma (SSA), traditional serrated adenoma (TSA), unclassified, and non-serrated adenoma type.

Results

There were significant differences between Groups A and B in terms of tumor size (27.6 vs. 43.1 mm), incidences of T1 carcinoma (71% vs. 13%), and having the same color as normal mucosa (47% vs. 17%), respectively (p <0.01). In SACs >20 mm, the incidence of T1 carcinoma in Group A (70%) was significantly greater than that in Group B (13%) (p <0.05). There were significant differences in ‘Japan NBI Expert Team’ type 3 and type V pit pattern classifications between the 2 groups. The average TSA-type tumor size (42.6 mm) was significantly larger than that of the SSA (17.2 mm) and non-serrated component types (18.3 mm). The incidences of submucosal invasion in SSA- (80%), unclassified- (100%), and non-serrated-type (100%) tumors were significantly higher than that in the TSA type (11%).

Conclusions

Epithelial serration in the cancerous area and a non-TSA background indicated aggressive behavior in early-stage SACs.

HIF-1α expression and high microvessel density are characteristic features in serrated colorectal cancer

Serrated colorectal adenocarcinoma (SAC) is a morphologically distinct subtype of colorectal cancer (CRC), in which increased HIF-1α mRNA expression and HIF-1α protein stabilization are typical features. Here we aimed to further elucidate HIF-1α protein expression in serrated and non-serrated colorectal carcinomas (CRCs) and their precursor lesions and its association with vascular endothelial growth factor (VEGF) and microvascular density (MVD). HIF-1α and VEGF expressions were determined immunohistochemically in 134 serrated polyps (SPs), 104 non-serrated adenomas (NSAs), 81 SACs, and 74 matched conventional adenocarcinomas (CCs) and were correlated with morphology, clinicopathological features, and MVD. In premalignant lesions, both HIF-1α and VEGF were expressed in the vast majority of SPs and NSAs. In CRCs, HIF-1α protein was also present in 77.8 % of SACs, while only 20.3 % of CCs were HIF-1α proficient. MVD was significantly higher in SACs, but the serrated morphology was the only significant predictor of MVD in CRC in multivariate analyses. HIF-1α protein is often stabilized in well-vascularized SACs, suggesting hypoxia-independent stabilization of HIF-1α. Moreover, HIF-1α stabilization did not associate with oncogenic activation of BRAF or KRAS or Von Hippel-Lindau (VHL) mutation. Prevalent HIF-1α expression in SAC and its precursors support the importance of HIF-1α-mediated pathways for the serrated route of colorectal carcinogenesis.

Biomarkers for the identification of precursor polyps of colorectal serrated adenocarcinomas

BACKGROUND

In contrast to conventional colorectal carcinomas (CCs), which develop through a so-called chromosome instability or suppressor phenotype pathway, the sequence of events leading from precursor polyps/adenomas to serrated adenocarcinomas (SACs), which are more aggressive and exhibit a poorer survival than CCs, is as yet not clearly defined. Here, we aimed at detecting protein and DNA biomarkers for SAC in a series of primary colorectal polyps.

METHODS

In total 303 colorectal polyps were included: 121 serrated polyps (33 hyperplastic polyps, 37 sessile serrated adenomas (SSA), 51 traditional serrated adenomas (TSA)), 143 conventional polyps (72 tubular polyps, 34 tubulovillous polyps, 37 villious adenomas), and 39 bi-phenotypic serrated-conventional polyps. The protein biomarkers tested were deduced from previously published SAC and CC expression profiling studies. A representative subset of 106 polyps was selected for DNA biomarker analyses, i.e., proto-oncogene mutation and microsatellite instability (MSI) status. In order to confer proper weight to each biomarker, a multivariate logistic regression model was employed.

RESULTS

We found that serrated and conventional polyps differed in most of the SAC biomarkers tested. Of these biomarkers, FSCN1 showed the largest difference in expression (p = 0.0001). Despite sharing a serrated morphology, we found that SSAs and TSAs differed considerably with respect to anatomical location, expression of EPHB2 and PTCH1, presence of the V600E BRAF mutation and MSI status. Logistic regression analysis revealed that SSA was the polyp type that shared most biomarkers with SAC.

CONCLUSION

Based on the shared presence of protein and molecular biomarkers, especially FSCN1 expression, SSA may serve as a precursor lesion of SAC. Biomarker assessment may help in discerning colorectal carcinogenic routes with distinct prognostic implications.

Clinical significance of programmed death ligand-1 (PD-L1) in colorectal serrated adenocarcinoma

Preliminary research results with antibody of the negative costimulatory molecule programmed cell death ligand-1 (PD-L1) suggested its expression on tumor cells associated with various tumor grade and postoperative prognosis. However, to date, there is no information of PD-L1 expression in colorectal serrated adenocarcinoma (SAC) and its clinical relevance. Therefore, the purpose of this study is to investigate the clinical significance of PD-L1 expression in a large cohort of patients with SAC. Here, we first retrospectively identified all SAC collected at our institution between August 2008 and May 2013. The expression levels of PD-L1 were examined by immunohistochemistry in 120 patients with SAC. We further evaluated the correlation between expression data and clinical parameters, including patient age, sex, tumor size, location, grade, primary tumor classification (pT), lymph node metastasis (pN), distant metastases (pM), and vascular invasion. Strong PD-L1 expression was detected in 25% of SAC. Higher expression of PD-L1 was significantly associated with pN (P=0.003) and pM (P=0.014). Survival analysis showed that patients with higher expression of PD-L1 had a poorer prognosis (P=0.045). However, multivariate regression analysis did not support PD-L1 as an independent prognostic factor (P=0.430). Our data suggest that PD-L1 may represent a new biomarker of metastasis and prognosis for patients with SAC, but as a target in the treatment of SAC is less certain.

Serrated neoplasia of the colorectum

Serrated polyps of the colorectum form a group of related lesions which include aberrant crypt foci (ACF), conventional hyperplastic polyps, mixed (admixed) polyps, serrated adenomas and sessile serrated adenomas. In recent years the molecular differences between these morphologically similar lesions have been highlighted, and their differing biological potential has been realised. In particular, the sessile serrated adenoma has become recognised as the precursor lesion to a group of sporadic colorectal carcinomas characterised by morphological and molecular features distinct from conventional adenomas. These recent findings have challenged the long held paradigm that all colorectal carcinomas arise via the traditional adenoma-carcinoma sequence. In addition, they present a major challenge for the early detection and management of colorectal cancer, which is no longer regarded as a homogeneous entity.