The prognostic value of leucine-rich repeat-containing G-protein (Lgr5) and its impact on clinicopathological features of colorectal cancer

Abstract

Introduction: Colorectal cancer (CRC) constitutes one of the most prevalent malignancies in the world. Recent research suggests that cancer stem cells (CSCs) are responsible for tumor cell's malignant behavior in CRC. This study has been designed to determinate clinical implications of CSC markers: CD44, DCLK1, Lgr5, and ANXA2 in CRC.

Materials and methods: The study was performed on tissue samples which were collected from 89 patients undergoing colectomy. Formalin-fixed paraffin-embedded tissue blocks with representative tumor areas were identified and corded. Immunohistochemical staining was performed using anti-CD44, anti-LGR5, anti-ANXA2, and anti-DCLK1 antibodies. The H-score system was utilized to determine the immunointensity of CRC cells.

Results: The lower expression of Lgr5 was significantly correlated with the presence of lymph-node metastases (p = 0.011), while high expression of Lgr5 was statistically significant in vascular invasion in examined cancer tissue samples (p = 0.027). Moreover, a high H-score value of Lgr5 expression was significantly related to a reduced overall survival rate (p = 0.043).

Conclusion: Our results suggest a strong relationship between CSC marker Lgr5 and vascular invasion, presence of lymph-node metastasis, and overall poor survival. The presence of Lgr5 might be an unfavorable prognostic factor, and its high level in cancer tissue is related to an aggressive course. This marker could also be used to access the effectiveness of the treatment.

Keywords: ANAX2; CD44; CSC; Colorectal cancer; DCLK1; Lgr5.

Fig. 1

Representative images of cancer stem cell markers by immunohistochemistry in colorectal cancer tissue with a low expression of Lgr5, b high expression of Lgr5, c low expression of DCLK1, d high expression of DCLK1, e low expression of ANAX2, f high expression of ANAX2, g low expression of CD44, and h high expression of CD44

Fig. 2

Median nuclear expression of Lgr5 for the studied groups according to regional lymph-node status. N0: colorectal cancers without nodal metastases, N1: colorectal cancers with 1–3 positive regional lymph nodes; N2: colorectal cancers with four or more positive regional lymph nodes

Fig. 3

Median nuclear expression of Lgr5 for the studied groups according to vascular invasion

Fig. 4

Stem cell marker expressions in primary tumor and overall survival in case of a Lgr5; b DCLK1; c ANXA2; and d CD44

Fig. 5

The cell adhesion is increased due to enhance levels of cortical F-actin in colorectal cancer cells with overexpression of Lgr5. The colorectal cancer cells could change their phenotype into mesenchymal-like with high expression of Snail, Slug, Zeb1 and 2, and N-cadherin and low expression of epithelial-associated genes such as E-cadherin after the downregulation of Lgr5 due to progressive CpG island methylation, what lead to epithelial–mesenchymal transition and induction of metastatic process (Walker et al. ; Carmon et al. ; Jang et al. ; Leng et al. 2018). EpCAM—epithelial cell adhesion molecule; Lgr5—leucine-rich repeat-containing G-protein-coupled receptor 5; ZEB1—zinc-finger E-box-binding homeobox 1; ZEB2—zinc-finger E-box-binding homeobox 2; Snail—zinc-finger protein SNAI; Snug—zinc-finger protein SNAI2; EMT—epithelial–mesenchymal transition