Standardization of a Preclinical Colon Cancer Model in Male and Female BALB/c Mice: Macroscopic and Microscopic Characterization from Pre-Neoplastic to Tumoral Lesions

<b>Background/Objetives:</b> This study standardized a chemically induced colorectal cancer (CRC) model using azoxymethane (AOM) and dextran sodium sulfate (DSS) in BALB/c mice, replicating the progression from preneoplastic lesions to adenocarcinoma observed in human colorectal carcinogenesis. <b>Methods:</b> The CCR-AOM/DSS model was standardized in male and female BALB/c mice. Two protocols were tested. Subsequently, the positive control group was established with nine evaluation points. Tumor progression was characterized histopathologically and corroborated by methylene blue staining and scanning electron microscopy. <b>Results:</b> Two cycles of 2% DSS combined with a single injection of AOM (10 mg/kg) were necessary to induce adenocarcinoma in 100% of the mice, with no significant sex-based differences in tumor development. Females showed earlier tumor susceptibility under certain protocols. Inflammatory processes played a critical role in tumorigenesis, with neutrophil infiltration and fibrosis observed. <b>Conclusions</b>: The findings align with previous reports, emphasizing the influence of DSS cycles, molecular weight, and mouse strain on model outcomes. This standardized model provides a reliable platform for the preclinical evaluation of novel preventive and therapeutic strategies for CRC.