Claudin 1 expression characterizes human uterine cervical reserve cells

Area of Science:

• Gynecologic pathology
• Cell biology
• Cancer research

Background:

• Stem cells, including endocervical reserve cells (RCs), are implicated in cervical carcinogenesis, but their precise functions and characteristics remain poorly understood.
• Tight junctions, crucial for epithelial cell adhesion, are composed of claudin proteins, whose expression is altered in cancer, yet their specific patterns in cervical cells are largely uncharacterized.

Purpose of the Study:

• To investigate the expression patterns of claudins (1, 2, 3, 4, 7) and other markers (occludin, cytokeratins 5/6 and 7, p63) in endocervical reserve cells (RCs) and their relationship with normal and neoplastic cervical cells.
• To elucidate the potential role of RCs in cervical carcinogenesis by analyzing their unique molecular signature.

Main Methods:

• Immunohistochemical analysis of 60 paraffin-embedded cervical tissue samples.
• Semiquantitative evaluation and statistical analysis of claudin, occludin, cytokeratin, and p63 expression in various cervical cell types, including RCs, glandular cells, squamous epithelial cells, and cervical intraepithelial neoplasia (CIN).

Main Results:

• Claudin 1 expression was high in RCs and CIN, exceeding that in suprabasal squamous cells, and was absent in glandular and squamous basal cells.
• Claudin 2 was broadly expressed, while claudins 3, 4, and 7 showed limited or weak expression across cell types.
• Occludin was detected in RCs, basal/parabasal cells, and CIN, but not in glandular cells. RCs exhibited an intermediate claudin pattern distinct from glandular and basal cells, but similar to neoplastic cells.

Conclusions:

• Endocervical reserve cells (RCs) possess a distinct claudin expression profile that differentiates them from normal cervical glandular and squamous basal cells.
• The observed claudin pattern in RCs, particularly the strong Claudin 1 expression, suggests a potential role in cervical carcinogenesis and warrants further investigation.
• This study provides the first detailed description of claudin expression in RCs, offering new insights into their biology and potential involvement in cervical cancer development.