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

Background: 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.

Aims: 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).

Methods: 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.

Results: 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).

Conclusions: 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.