# ALDH1 and ALCAM as emerging biomarkers in personalized rectal cancer therapy

## TL;DR

The study explores ALDH1 and ALCAM as potential biomarkers in rectal cancer, finding elevated levels in patients but limited correlation with tumor stage or survival.

## Contribution

The study investigates ALDH1 and ALCAM as novel serum biomarkers for rectal cancer prognosis and therapy monitoring.

## Key findings

- Serum levels of ALCAM and ALDH1 were elevated in rectal cancer patients compared to healthy controls.
- No significant correlation was found between biomarker levels and tumor stage or patient survival.
- Biomarker expression in tumor tissues increased with advanced UICC stages.

## Abstract

The preoperative evaluation of serum tumor markers provides valuable prognostic and therapeutic insights in solid malignancies. Although not diagnostic by themselves, increased preoperative concentrations often reflect greater tumor burden, advanced disease stage, and unfavorable clinical outcomes.

The aim of this study was to investigate the expression and diagnostic-prognostic potential of the tumor markers aldehyde dehydrogenase 1 (ALDH1) and activated leukocyte cell adhesion molecule (ALCAM) in the blood of rectal cancer patients under the influence of short- or long-term radio-/chemoradiotherapy (RTx/RCTx).

Serum samples taken from patients with rectal carcinoma (n=164) at different time points during and after RTx/RCTx were retrospectively examined to determine whether these markers could predict disease progression and long-term survival.

Kaplan-Meier analysis confirmed the prognostic relevance of the Union for International Cancer Control (UICC) staging, while no significant associations were observed between serum levels of the investigated biomarkers and individual patient or tumor characteristics such as age, sex, or tumor stage. Overall, ALCAM and ALDH1 in this limited patient cohort exhibited elevated serum levels compared with healthy controls, and tumor tissues demonstrated stage-dependent increases in marker expression (UICC III/IV versus I/II).

Serum concentrations of ALCAM and ALDH1 were significantly elevated in our patient cohort with rectal cancer but showed no significant correlation with tumor stage or survival, whenever serum samples were obtained either during or after neoadjuvant and adjuvant therapy, which may be particularly due to the limited number of studied subjects. Although their prognostic utility remains limited, their consistent elevation in cancer patients underscores their potential value in early detection or as components of a broader biomarker panel.

Rectal cancer continues to represent a major public health issue worldwide, with incidence rising progressively with advancing age.

The preoperative evaluation of serum tumor markers offers significant prognostic and therapeutic insights in patients with solid neoplasms.

Carcinoembryonic Antigen (CEA) remains a well-established prognostic indicator in colorectal cancer.

Cancer stem cells (CSCs) have emerged as pivotal elements in the onset, progression, and recurrence of malignant tumors.

Multiple markers have been proposed in CRC as indicative of CSC activity, including CD44, CD24, CD133, CD166, ALCAM, EpCAM, LGR5, and ALDH1.

Rectal cancer is a major global health concern, with incidence increasing alongside aging populations. Although the overall 5-year survival rate is only slightly higher than that of colon cancer, stage-specific outcomes remain comparable between the two entities. Nevertheless, patients with rectal carcinoma exhibit a greater propensity for locoregional recurrence and, in many cases, distant metastatic spread, despite continuous advances in multimodal treatment strategies.

The evaluation of serum biomarkers such as aldehyde dehydrogenase 1 (ALDH1) and activated leukocyte cell adhesion molecule (ALCAM) offers new insights into the biological behavior of rectal cancer. Their analysis may contribute to refining prognostic assessment and therapeutic monitoring, ultimately advancing the development of more individualized approaches for patients undergoing neoadjuvant and adjuvant therapies.