High levels of microRNA-21 in the stroma of colorectal cancers predict short disease-free survival in stage II colon cancer patients

Abstract

Approximately 25% of all patients with stage II colorectal cancer will experience recurrent disease and subsequently die within 5 years. MicroRNA-21 (miR-21) is upregulated in several cancer types and has been associated with survival in colon cancer. In the present study we developed a robust in situ hybridization assay using high-affinity Locked Nucleic Acid (LNA) probes that specifically detect miR-21 in formalin-fixed paraffin embedded (FFPE) tissue samples. The expression of miR-21 was analyzed by in situ hybridization on 130 stage II colon and 67 stage II rectal cancer specimens. The miR-21 signal was revealed as a blue chromogenic reaction, predominantly observed in fibroblast-like cells located in the stromal compartment of the tumors. The expression levels were measured using image analysis. The miR-21 signal was determined as the total blue area (TB), or the area fraction relative to the nuclear density (TBR) obtained using a red nuclear stain. High TBR (and TB) estimates of miR-21 expression correlated significantly with shorter disease-free survival (p = 0.004, HR = 1.28, 95% CI: 1.06–1.55) in the stage II colon cancer patient group, whereas no significant correlation with disease-free survival was observed in the stage II rectal cancer group. In multivariate analysis both TB and TBR estimates were independent of other clinical parameters (age, gender, total leukocyte count, K-RAS mutational status and MSI). We conclude that miR-21 is primarily a stromal microRNA, which when measured by image analysis identifies a subgroup of stage II colon cancer patients with short disease-free survival.Electronic supplementary materialThe online version of this article (doi:10.1007/s10585-010-9355-7) contains supplementary material, which is available to authorized users.

miR-185 and miR-133b deregulation is associated with overall survival and metastasis in colorectal cancer

“…The discrepancy may be due to the differences in location of tumor site or tumor histological subtype. In line with this statement, the association of poor survival and miR-21 over-expression was only documented in colon cancer (24,43), but not in rectal cancer (43). In addition, high expression of miR-21 was also detected in adenocarcinoma sub-type (24).…”

“…Due to the limited number of cases, we could not ascertain its expression in relation to tumor site and histological subtype. Interestingly, Nielsen et al observed that the expression of miR-21 was predominantly found in fibroblast-like cells located in the stromal compartment of the colon tumors (43). The cellular context of the tumors analyzed may also contribute to the discrepancy.…”

MicroRNA Classifier and Nomogram for Metastasis Prediction in Colon Cancer

“…miRNA-21-5p was previously reported to show increased expression in tumor compared with normal colon mucosa (37), and was linked to early onset carcinogenesis (38). Two independent manuscripts reported that increased expression of miR21, predominantly in the stroma compartment and not the cancer cells, is associated with clinical outcome in TNM stage II colon cancer patients (39,40). These findings might explain why we did not see an association between miR21 expression and metastasis risk, unlike others (24).…”

Modulation of Cancer Progression by Tumor Microenvironmental Leukocyte-Expressed microRNAs

“…We and others have implemented similar in situ hybridization (ISH) methods to identify the cellular compartment(s) of altered miRNA expression in a variety of solid tumors, including brain, breast, colorectal, lung, pancreatic, and prostate cancer (Dillhoff et al, 2008;Donnem et al, 2011;Gupta & Mo, 2011;Habbe et al, 2009;Jorgensen et al, 2010;Liu et al, 2010a;Nelson et al, 2006Nelson et al, , 2010Nelson & Wilfred, 2009;Nielsen et al, 2011;Preis et al, 2011;Qian et al, 2011;Rask et al, 2011;Schepeler et al, 2008;Schneider et al, 2011;Sempere et al, 2007Sempere et al, , 2010Yamamichi et al, 2009). miR-21 and miR-155 are frequently detected at higher levels in solid tumors and their differential expression correlates with outcome (Barbarotto et al, 2008;Sempere, 2011).…”