Expression of the intestinal biomarkers Guanylyl cyclase C and CDX2 in poorly differentiated colorectal carcinomas

Brody Winn, Rosemarie Tavares, Andres Matoso, Lelia Noble, Jacqueline Fanion, Scott A. Waldman, Murray B. Resnick

Research output: Contribution to journalArticlepeer-review


Guanylyl cyclase C, a receptor for bacterial diarrheagenic enterotoxins, is expressed selectively by intestinal epithelium and is an endogenous downstream target of CDX2. The expression of Guanylyl cyclase C is preserved throughout the adenoma/carcinoma sequence in the colorectum. Detection of Guanylyl cyclase C expression by reverse transcriptase-polymerase chain reaction is currently being validated as a technique to identify occult lymph node metastases in patients with colorectal cancer and for circulating cells in the blood for postoperative surveillance. Although Guanylyl cyclase C is widely expressed by well-differentiated colorectal cancer, its expression in poorly differentiated colorectal cancer has not been evaluated. A tissue microarray was created from 69 archival specimens including 44 poorly differentiated, 15 undifferentiated or medullary, and 10 signet ring cell colorectal carcinomas. Matched normal colonic mucosa was used as a positive control. Immunohistochemical staining for Guanylyl cyclase C and CDX2 was evaluated as positive or negative based on at least a 10% extent of staining. Of the 69 tumor samples, 75%, 47%, and 90% of the poorly differentiated, medullary, and signet ring cell tumors were positive for Guanylyl cyclase C and 75%, 40% and 90% of these subsets were positive for CDX2, respectively. There was excellent correlation between Guanylyl cyclase C and CDX2 expression on a case-per-case basis (P < .0001). There was also a statistically significant difference in the Guanylyl cyclase C staining pattern between medullary carcinomas and poorly differentiated, not otherwise specified (P = .05). Immunopositivity for Guanylyl cyclase C was greater than 95% in a separately stained microarray series of well/moderately differentiated colorectal carcinomas. In conclusion, Guanylyl cyclase C expression is lost in a quarter of poorly differentiated and half of undifferentiated colorectal carcinomas. Therefore, the utility of Guanylyl cyclase C expression as a diagnostic marker for colorectal carcinoma may be questionable in poorly differentiated colorectal neoplasms.

Original languageEnglish (US)
Pages (from-to)123-128
Number of pages6
JournalHuman pathology
Issue number1
StatePublished - Jan 2010
Externally publishedYes


  • CDX2
  • Carcinoma
  • Colon
  • Guanylyl cyclase C
  • Poorly differentiated

ASJC Scopus subject areas

  • Pathology and Forensic Medicine


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