Scholarlink

Background <p>Sessile serrated lesions (SSLs) are recognized as precursors in the serrated neoplastic pathway leading to microsatellite instability-high colorectal cancer. A hallmark feature of SSLs on endoscopic examination is the mucous cap.</p> Aims <p>We aimed to investigate the expression of the bicarbonate transporters SLC26A3 and CFTR in SSLs, using immunohistochemistry to elucidate their potential involvement in the pathogenesis of mucous cap formation.</p> Methods <p>We analysed 14 SSLs from 12 patients using formalin-fixed, paraffin-embedded tissue sections. Histochemical staining with high-iron diamine-Alcian blue (HID-AB) and immunohistochemistry for MUC2, MUC5AC, SLC26A3, and CFTR were conducted.</p> Results <p>In normal colonic mucosa, MUC2 was strongly expressed in goblet cells, whereas MUC5AC was absent. SLC26A3 was expressed on the apical membrane and in the cytoplasm of surface epithelial and upper crypt cells, while CFTR was localized to the apical membrane of epithelial cells along the crypt axis. In SSLs, crypts showed architectural distortion with mucin retention in the dilated lumina and an overlying mucous cap. HID-AB staining revealed the presence of sulfomucins and sialomucins. Goblet cells coexpressed MUC2 and MUC5AC, with MUC2 showing broader and stronger expression. These mucins showed a partially distinct and mutually exclusive distribution. Notably, SLC26A3 and CFTR expression levels were markedly reduced or absent in SSLs.</p> Conclusion <p>SSLs showed a mixed acidic mucin phenotype and downregulated epithelial bicarbonate transporters. This may impair mucin expansion and hydration, leading to the formation of adhesive mucous caps, showing the potential link between defective bicarbonate transport and mucin physiology in SSLs.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Impaired Bicarbonate Transport via SLC26A3 and CFTR Downregulation Promotes Mucous Cap Formation in Sessile Serrated Lesions

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2025年10月17日

查看全文
  • Hiroyoshi Ota,
  • Miharu Suzuki,
  • Heiwa Tanabe,
  • Yukiko Kusama,
  • Ayako Seki,
  • Etsuo Hara,
  • Takeshi Uehara

摘要

Background

Sessile serrated lesions (SSLs) are recognized as precursors in the serrated neoplastic pathway leading to microsatellite instability-high colorectal cancer. A hallmark feature of SSLs on endoscopic examination is the mucous cap.

Aims

We aimed to investigate the expression of the bicarbonate transporters SLC26A3 and CFTR in SSLs, using immunohistochemistry to elucidate their potential involvement in the pathogenesis of mucous cap formation.

Methods

We analysed 14 SSLs from 12 patients using formalin-fixed, paraffin-embedded tissue sections. Histochemical staining with high-iron diamine-Alcian blue (HID-AB) and immunohistochemistry for MUC2, MUC5AC, SLC26A3, and CFTR were conducted.

Results

In normal colonic mucosa, MUC2 was strongly expressed in goblet cells, whereas MUC5AC was absent. SLC26A3 was expressed on the apical membrane and in the cytoplasm of surface epithelial and upper crypt cells, while CFTR was localized to the apical membrane of epithelial cells along the crypt axis. In SSLs, crypts showed architectural distortion with mucin retention in the dilated lumina and an overlying mucous cap. HID-AB staining revealed the presence of sulfomucins and sialomucins. Goblet cells coexpressed MUC2 and MUC5AC, with MUC2 showing broader and stronger expression. These mucins showed a partially distinct and mutually exclusive distribution. Notably, SLC26A3 and CFTR expression levels were markedly reduced or absent in SSLs.

Conclusion

SSLs showed a mixed acidic mucin phenotype and downregulated epithelial bicarbonate transporters. This may impair mucin expansion and hydration, leading to the formation of adhesive mucous caps, showing the potential link between defective bicarbonate transport and mucin physiology in SSLs.