Colorectal adenomas produce lysozyme

Area of Science:

• Gastroenterology
• Oncology
• Molecular Pathology

Background:

• Lysozyme is an innate antibacterial enzyme primarily found in the upper intestinal tract.
• Its secretion is not typical in the lower intestinal tract, but previous studies suggest it may occur in colorectal neoplasias.

Purpose of the Study:

• To investigate and audit lysozyme expression in various colorectal diseases, focusing on neoplasias.
• To compare lysozyme overexpression across normal mucosa, inflammatory conditions, and different types of polyps and carcinomas.

Main Methods:

• Immunohistochemical staining of 177 colorectal tissue sections for lysozyme (Muramidase), Ki67 (MIB1), and CD 68.
• Quantitative comparison of intense lysozyme overexpression (+++) across different tissue types.

Main Results:

• Intense lysozyme overexpression (+++) was detected in 97.6% of tubular adenomas, 88.9% of serrated adenomas, 93.3% of villous adenomas, and 76.9% of carcinomas.
• Overexpression was also found in 9.5% of hyperplastic polyps but not in normal mucosa, regenerative mucosa, inflammatory polyps, collagenous colitis, or melanosis coli.
• Two hyperplastic polyps showed intense lysozyme overexpression, hinting at potential dysplastic evolution.

Conclusions:

• Neoplastic colorectal cells can acquire lysozyme production capacity, suggesting a role beyond antibacterial function.
• Lysozyme overexpression may be a significant event in mutated colorectal cells, potentially influencing tumor behavior.
• The findings warrant further investigation into the prognostic implications of lysozyme expression in colorectal cancer and its role in hyperplastic polyp progression.