CD133 and CD166 Stem Cells Markers Expression, Clinicopathological Parameters, and Fragmentation Response Patterns of ypT3 Rectal Cancer Following Neoadjuvant Chemoradiotherapy

Abstract

Background: The effectiveness of neoadjuvant chemoradiotherapy (nCRT) is variable in locally advanced rectal cancer (LARC) patients, the ypT3 stage having a minimal or moderate response. The aim of our study was the evaluation of the association between CD133 (Prominin1) and CD166 (ALCAM) expression, survival parameters, and clinicopathological characteristics of a subgroup of LARC patients who achieved ypT3, showing post-nCRT and TME tumor fragmentation response and the assessment of these CSCs biomarkers value as indicators of the nCRT tumor response. Methods: Our study group comprised 60 LARC patients who achieved ypT3 status and exhibited a tumor fragmentation pattern following nCRT. Clinicopathological parameter and survival evaluations, along with CD133 and CD166 immunohistochemistry and scoring, were performed and the associations between different parameters were tested. Results: High CD133 expression was significantly associated with ypN category (p = 0.018), lymphovascular invasion (LVI) (p = 0.009), perineural invasion (PnI) (p = 0.006), and tumor grading (p = 0.047), while high CD166 expression was significantly associated with LVI (p = 0.020) and PnI (p = 0.028). Tumors with high CD133 and CD166 expressions were associated with decreased overall survival (OS) (p = 0.004 and p = 0.006). Cox regression analysis identified high CD133 and CD166 expression as independent factors associated with reduced survival (HR = 3.237, p = 0.014 and HR = 2.866, p = 0.020). Conclusions: Our results support the hypothesis that CD133 and CD166 are putative CSC biomarkers associated with aggressive behavior and a poor prognosis in LARC, offering opportunities for personalized targeted therapies.

Keywords: CD133; CD166; LARC; fragmentation pattern; immunohistochemistry; neoadjuvant chemoradiotherapy; rectal cancer; ypT3 stage.

Figure 1

Lymphovascular invasion (arrow) in a ypT3-stage LARC case (H&E staining, 200×).

Figure 2

Perineural invasion (arrow) in a ypT3-stage LARC case (H&E staining, 200×).

Figure 3

Individual and small clusters of tumor cells (arrows) at the invasive tumor front in a ypT3-stage LARC case (Bd2) (H&E staining, 200×).

Figure 4

A few groups of tumor cells (arrows), consisting of at least five cells, located at the invasive tumor front in a ypT3-stage LARC case (PDC1) (H&E staining, 200×).

Figure 5

Luminal membrane CD133-positive immunoexpression (arrow) in more than 50% of the tumor area in a ypT3-stage LARC case (200×).

Figure 6

Luminal membrane (arrow) and cytoplasmic CD133-positive immunoexpression in more than 50% of the tumor area in a ypT3-stage LARC case (400×).

Figure 7

Negative CD133 immunoexpression (arrow) of a ypT3-stage LARC case (400×).

Figure 8

Strong CD166 immunoexpression of a ypT3-stage LARC case (200×).

Figure 9

Moderately positive CD166 immunoexpression of a ypT3-stage LARC case (100×).

Figure 10

Weak CD166 immunoexpression of a ypT3-stage LARC case (40×).

Figure 11

Kaplan–Meier survival curves for OS of ypT3-stage LARC patients with low or high CD133 expression.

Figure 12

Kaplan–Meier survival curves for OS of ypT3-stage LARC patients with low or high CD166 expression.

Figure 13

Potential mechanisms behind CD133+/CD166+ CRC CSCs’ involvement in therapy resistance. CRC—colorectal cancer; CSCs—cancer stem cells; CD—cluster of differentiation; PTCH1—transmembrane receptor PATCHED1; Shh—sonic Hedgehog protein; ↑—increase; ↓—decrease.