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Usefulness of CDX2 and TTF-1 in Differentiating Gastrointestinal From Pulmonary Carcinoids

Anjali Saqi MD, Diane Alexis, Fabrizio Remotti MD, Govind Bhagat MD
DOI: http://dx.doi.org/10.1309/UKN6PVRKXHG422DA 394-404 First published online: 1 March 2005


Carcinoids of different organs appear morphologically indistinguishable. We studied the differential expression of CDX2 and thyroid transcription factor-1 (TTF-1) in 78 gastrointestinal and pulmonary carcinoids and their metastases (n = 10). CDX2 staining of gastric biopsy specimens with neuroendocrine hyperplasia (n = 11) and various gastritides (n = 10) was also performed. All ileal (6/6 [100%]), 6 (86%) of 7 appendiceal, 3 (75%) of 4 duodenal, 1 (50%) of 2 ampullary, 12 (33%) of 18 rectal, 5 (26%) of 19 pancreatic, and 1 (17%) of 6 gastric carcinoids expressed CDX2 with variable intensity; none of the pulmonary carcinoids stained. Of 15 pulmonary carcinoids, 8 (53%) stained with TTF-1, but none of the gastrointestinal carcinoids did. CDX2 and TTF-1 staining profiles of primary and metastatic carcinoids were similar. CDX2+ gastric endocrine cells had a distribution similar to that of gastrin and enterochromaffin cells but not enterochromaffin-like cells. Our results suggest that CDX2 and TTF-1 have high specificity for gastrointestinal and pulmonary carcinoids, respectively.

Key Words:
  • Carcinoid
  • CDX2
  • Intestine
  • Lung
  • Pancreas
  • Stomach
  • Thyroid transcription factor-1
  • TTF-1