CDX-2

CDX are homeobox genes essential to intestinal organogenesis and encode nuclear transcription factors6. CDX-2 is analogous to the Drosophila gene caudal. Two genes have been identified in humans (CDX-1 and CDX-2) and a third gene (CDX-4) in mice9. CDX2-knockout mice show that the absence of the gene (-/-) is lethal in utero, while heterozygotes (+/-) show focal loss of intestinal differentiation22 and develop hamartomas and neoplasms of the colon9. CDX-1 appears to be responsible for proliferation and CDX-2 for differentiation of intestinal epithelium8. CDX-2 appears to promote expression of the proglucagon gene7, colon carbonic anhydrase-130, sucrase-isomaltase23 and lactase23, and to act as a tumour suppressor gene, downregulated in colonic carcinoma10. It interacts with the tumour suppressor genes APC12 and E-cadherin13, as well as bcl-211.

A monoclonal antibody is available which is effective on formalin-fixed paraffin-embedded tissue. Immunoreactivity for CDX-2 is nuclear, accompanied by faint cytoplasmic staining in some cases. Recently, two substantial paper on the diagnostic use of CDX-2 has been published1,2; it appears promising and the findings of these papers are underpinned by more basic biological papers on this homeobox gene. The subject has been reviewed17.

The use of the proprietary Trilogy antigen retrieval buffer containing EDTA gives a higher rate of staining in lung tumours than does a citrate buffer: the results with the Trilogy buffer accord more closely with the assessment of CDX-2 gene expression30.

Immunohistochemical expression

normal tissues:
- with the exception of those listed below, normal tissues are NEGATIVE for CDX-223.
- CDX-1 and CDX-2 are both broadly expressed in the fetus but by the early neonatal period become restricted to the small and large bowel and pancreas. CDX-1 is predominantly expressed in the base of crypts and CDX-2 higher, in the crypt tip5 and villi. CDX-2 positivity is seen in intestinal epithelial cells from duodenum to rectum23, including absorptive, goblet, (neuro)endocrine26 and Paneth cells. The CDX-2 gene is more strongly expressed in the small intestine and caecum, less intensely in the distal colon5.
- Scattered cells are positive in pancreatic ductules23. Scattered cells are occasionally positive in the gallbladder (1 of 5 cases)2.
- There is no nuclear reactivity in liver, stomach22 (except within intestinal metaplasia), thyroid, parathyroid, adrenal, pancreatic islets, alveolar cells, bronchial epithelium, urogenital tract, squamous epithelium (skin, larynx, oesophagus[except within intestinal metaplasia], vagina, cervix), lymphoid tissue, CNS and peripheral nerves. Cytoplasmic staining for CDX-1 has been reported in scattered cells in the gastric antrum22. Supra-nuclear Golgi staining occurs in the normal gastric glands and in most of the cells of the foveolar epithelium of the antrum22.
Gastric intestinal metaplasia shows ectopic overexpression of both CDX-1 (in 47/523 and 18/1822 cases) and CDX-2(in 41/483 and 17/1822 cases): the CDX-2 immunoreactivity is not abolished by the eradication of Helicobacter pylori19. There is no difference in the staining between complete and incomplete intestinal metaplasia22. Diffuse cytoplasmic and Golgi staining for both CDX-1 and CDX-2 may accompany the nuclear staining22. In gastritis, the mucosa shows fine granular cytoplasmic staining in both the presence and absence of intestinal metaplasia19. Expression of CDX-2 is reportedly greater in complete intestinal metaplasia than it is in incomplete intestinal metaplasia (with its greater risk of progression to carcinoma) or in dysplasia29:

	Reference 29	CDX-2 score
	Normal gastric mucosa	0
	Complete intestinal metaplasia	8
	Incomplete intestinal metaplasia	6
	Gastric dysplasia	3.9
	Gastric carcinoma	3.1

The normal oesophageal mucosa is negative18. Barrett's oesophagus shows strong nuclear and fine granular cytoplasmic staining, while inflamed oesophagus without intestinal metaplasia shows only fine granular cytoplasmic staining18.


	Glandular metaplasia of the oesophagus without goblet cells	17/4528
	Strips of superficial Alcian blue positive columnar mucosal cells devoid of goblet cells	0/1128
	Barrett's oesophagus (intestinal metaplasia with goblet cells)	45/4528

From this study it was argued that CDX-2 identifies form fruste intestinal metaplasia prior to the development of goblet cells!28

Granular cytoplasmic positivity has been reported in epithelial mucosa in the inflamed gallbladder and nuclear positivity in intestinal metaplasia of the gallbladder25.
Neoplasms:

One paper uses a cutoff of 25% of tumour cells positive2. In order to render the papers comparable, I have presented the results showing any degree of positivity for CDX-2 as positive.

Adenocarcinomas	Colorectum	58/601, 30/301, 75/752, 13/1314, 84%15, 100%(metastatic to liver)16, 21/2121, 60/6023, 24/25(differentiated adenocarcinomas)24, 13/1330, 39/4750
	Colorectal large cell minimally differentiated carcinoma	2/1524
	Gastro-oesophageal	76/16423
	Oesophagus	6/92, 4/514, 4/530, 2/2150
	Stomach	11/201, 17/242, 38/693, 9/1214, 25/4622, 9/1230, 6/3450
	Duodenum	4/4(more than 75% of tumour cells stained)2
	Ampullary carcinoma	4/623, 4/630, 1/650
	Pancreas	3/51, 7/222, 2/1014, 0%15, 0%16, 9/2723, 1/830, , 0/5350
	Gallbladder, cholangiocarcinoma	3/5(gallbladder)1, 4/162, 0%15, 11/2323, 1/1050
	Hepatocellular	0/122, 0%15, 0%16, 0/12(using tissue microarrays)23, 0/650
	Ovary, mucinous adenocarcinoma	5/51, 11/142, 9/1114, 11%15, 1/523, 9/1130, 2/1050
	Ovary, serous adenocarcinoma	0/51, 2%15, 2/4123, 0/530, 0/1850
	Ovary, non-mucinous, NOS	1/362, 0/514
	Ovary, endometrioid	3/1023
	Ovary, clear cell	1/224
	Ovary, undifferentiated	0/7(using tissue microarrays)23
	Endometrial	1/1014, 9%15, 4/2223, 1/1030, 0/1050
	Endocervical	no reports yet
	Breast	0/201, 0/10(metastatic to lung)1, 0/342, 0/2214, 0%15, 0/70(using tissue microarrays)23, 0/10(metastatic to brain)49, 0/29(9 mucinous, 20 non-mucinous)30, 0/3550
	Prostate	0/51, 0/3(metastatic to lung)1, 5/272, 0%15, 2/10223, 0/1850
	Bladder adenocarcinoma	3/3(including one urachal carcinoma)2
	Kidney	0/5(metastatic to lung)1, 0/72, 0%15, 0/35(using tissue microarrays)21, 0/1550
	Sinonasal intestinal type	no reports yet.
	Thyroid	0/4(metastatic to lung)1, 1/362, 0%15, 0/2123
Adenoma	Duodenum	10/10(more than 75% of tumour cells stained)2
	Colorectum	98%15
	Ovary, mucinous cystadenoma	1/132
	Ovarian benign mucinous tumour of endocervical type	0/4720
	Ovarian benign mucinous tumour of intestinal type	3/320
	Ovary, mucinous borderline tumour	1/42
Gastrointestinal neuroendocrine tumours	Gastric neuroendocrine hyperplasia	3/526
	Gastrointestinal carcinoid, various sites	7/122, 16/2223
	Gastric well differentiated neuroendocrine tumour	5/526
	Gastric neuroendocrine carcinoma	6/726
	Duodenal well differentiated neuroendocrine tumour	4/426
	Ileal well differentiated neuroendocrine tumour	14/1426
	Small intestinal neuroendocrine carcinoma	2/226
	Appendiceal well differentiated neuroendocrine tumour	6/626
	Colonic well differentiated neuroendocrine tumour	0/126
	Colonic neuroendocrine carcinoma	5/526
	Rectal well differentiated neuroendocrine tumour	7/926
	Pancreatic islet cell tumours, NOS	4/1423
	Pancreatic functioning well differentiated neuroendocrine tumour	0/1326
	Pancreatic non-functioning well differentiated neuroendocrine tumour	14/4826
	Pancreatic islet cell tumour	4/1423
	Liver neuroendocrine carcinoma	1/126
Lung primaries	Neuroendocrine hyperplasia	0/526
	Squamous cell carcinoma	0/101, 0/112, 3/4121, 0/13(using tissue microarrays)23, 0/750
	Adenosquamous carcinoma	0/521
	Adenocarcinoma NOS	0/112, 2/1214, 29/21221, 0/3523, 7/5530, 0/22(metastatic to brain)49, 1/4650
	Acinar adenocarcinoma	0/371
	Papillary adenocarcinoma	0/61
	Mucinous	1/22, 11/114, 0/24
	Bronchoalveolar carcinoma	0/28(8 mucinous, 15 non-mucinous, 5 mixed)1
	Large cell carcinoma	0/101, 0/621, 0/1(using tissue microarrays)23
	non-small cell and NOS	4/332, 1<1%15
	Small cell carcinoma	0/101, 0/42, 3/1621, 0/2(using tissue microarrays)23, 1/86, 0/350
	Large cell neuroendocrine carcinoma	3/821, 5/86
	Carcinoid	0/51, 1/821, 2/7(<25% of cells in both cases)23, 0/3026
	Mucoepidermoid carcinoma	0/11
	Carcinoma other than adenocarcinoma	3/2930
Mesothelioma		0/51, 0/72, 0/28(using tissue microarrays)24, 0/650
Other lung tumours	Sclerosing haemangioma	0/51
	Epithelioid haemangioendothelioma	0/21
	Alveolar adenoma	0/11
	Blastoma	0/21
Other carcinomas	transitional cell carcinoma of bladder	3/212, 2%15, 0/7(using tissue microarrays)23
	head and neck squamous cell carcinoma	0/132
	oesophageal squamosu cell carcinoma	0/750
	sarcomatoid carcinoma, various sites	0/14(using tissue microarrays)23
Other neuroendocrine tumours	Bladder neuroendocrine carcinoma	4/1026
	Uterine neuroendocrine carcinoma	2/326
	Prostatic neuroendocrine carcinoma	2/526
	Breast neuroendocrine carcinoma	1/326
	Skin, Merkel cell carcinoma	1/1526
Salivary gland	salivary gland pleomorphic adenoma	0/62
	acinic cell tumour	0/4(using tissue microarrays)23
	adenoid cystic carcinoma	0/17(using tissue microarrays)23
	polymorphous low grade carcinoma	0/3(using tissue microarrays)23
	low grade carcinoma	0/62
	salivary duct carcinoma
	neuroendocrine carcinoma	1/326
Germ cell tumours	Dysgerminoma	1/423
	Embryonal carcinoma	0/3(using tissue microarrays)23
	Seminoma	0/6(using tissue microarrays)23
	Yolk sac tumour	4/523
Ovary, granulosa cell tumour		0/8(using tissue microarrays)23
Melanoma		0%15, 0/1(using tissue microarrays)23
Paraganglioma		0/626
Phaeochromocytoma		0/426
Adrenal cortical adenoma		0/126
Thyroid carcinomas		0/1226
Parathyroid adenoma		0/226

There is loss of CDX-2 expression in a small proportion of colonic carcinomas and in some series, poorly differentiated adenocarcinomas in patients with microsatellite instability tend to show less expression than better differentiated tumours1, although others have not found a correlation with the grade of tumour2.

CDX-1 was expressed in 51 of 69 gastric adenocarcinomas and more often in intestinal than diffuse type gastric carcinomas3.

CDX-2 positivity in lung carcinomas is associated with CK20 positivity, male gender, size >30 mm and lack of TTF-1 expression21. Positivity of adenocarcinomas for CDX-2 and CK20, albeit with retention of CK7, at sites outside the gastrointestinal tract, may be a manifestation of the acquisition of an intestinal phenotype.

Positivity for CDX-2 occurs in a minority of neuroendocrine carcinomas outside the gastrointestinal site, without an apparent relation to the site26.

Diagnostic utility

Identification of the primary site of a metastatic adenocarcinoma, and differentiation from a primary adenocarcinoma of lung, in combination with TTF-1, CK7 and CK20. CDX2 does not reliably differentiated between colorectal, other gastrointestinal, mucinous ovarian and bladder adenocarcinomas. It may be useful in combination with villin: if negative for both, very unlikely to be from a gastrointestinal primary. If there is positivity for CDX2 (with or without villin immunoreactivity) it is likely to be from a colorectal primary. However, note the caveats associated with primary mucinous tumours of the lung and intestinal type sinonasal adenocarcinoma. Variable staining for both CDX2 and villin suggests origin from elsewhere in the gastrointestinal tract2. Nuclear immunoreactivity for CDX2 and TTF-1 is particularly useful in interpreting cytological specimens from metastatic colorectal carcinoma to lung1. As a member of a panel to differentiated primary ovarian endometrioid/mucinous carcinoma of the ovary from metastatic colorectal carcinoma.
Identification of the site of origin of a well differentiated neuroendocrine tumour: tumours of the ileum and appendix are strongly positive, those of the stomach, colorectum and pancreas are variable and all others are negative26. For high grade tumours, most gastrointestinal neuroendocrine carcinomas are positive, but so are a minority of those from other sites26.
Possibly in the identification of high-risk intestinal metaplasia of the gastric mucosa29.
There is little published data on the diagnostic value of CDX-13.

References

1 Barbareschi, M., Murer, B., Colby, T.V., Chilosi, M., Macri, E., Loda, M. and Doglioni, C. CDX-2 Homeobox Gene Expression Is a Reliable Marker of Colorectal Adenocarcinoma Metastases to the Lungs. Am J Surg Pathol 2003;27:141-9.

2 Werling, R.W., Yaziji, H., Bacchi, C.E. and Gown, A.M. CDX2, a Highly Sensitive and Specific Marker of Adenocarcinomas of Intestinal Origin: An Immunohistochemical Survey of 476 Primary and Metastatic Carcinomas. Am J Surg Pathol 2003;27:303-10.

3 Bai, Y.Q., Yamamoto, H., Akiyama, Y., Tanaka, H., Takizawa, T., Koike, M., Kenji Yagi, O., Saitoh, K., Takeshita, K., Iwai, T. and Yuasa, Y. Ectopic expression of homeodomain protein CDX2 in intestinal metaplasia and carcinomas of the stomach. Cancer Lett 2002;176:47-55.

4 Rossi G, presentation to Pulmonary Pathology Club, Chester, UK, 13.6.03; paper submitted.

5 James, R., T. Erler, et al. (1994). "Structure of the murine homeobox gene cdx-2. Expression in embryonic and adult intestinal epithelium." J Biol Chem 269(21): 15229-37.

6 Freund, J. N., C. Domon-Dell, et al. (1998). "The Cdx-1 and Cdx-2 homeobox genes in the intestine." Biochem Cell Biol 76(6): 957-69.

7 Jin, T. and D. J. Drucker (1996). "Activation of proglucagon gene transcription through a novel promoter element by the caudal-related homeodomain protein cdx-2/3." Mol Cell Biol 16(1): 19-28.

8 Suh, E. and P. G. Traber (1996). "An intestine-specific homeobox gene regulates proliferation and differentiation." Mol Cell Biol 16(2): 619-25.

9 Chawengsaksophak, K., R. James, et al. (1997). "Homeosis and intestinal tumours in Cdx2 mutant mice." Nature 386(6620): 84-7.

10 Mallo, G. V., H. Rechreche, et al. (1997). "Molecular cloning, sequencing and expression of the mRNA encoding human Cdx1 and Cdx2 homeobox. Down-regulation of Cdx1 and Cdx2 mRNA expression during colorectal carcinogenesis." Int J Cancer 74(1): 35-44.

11 Mallo, G. V., P. Soubeyran, et al. (1998). "Expression of the Cdx1 and Cdx2 homeotic genes leads to reduced malignancy in colon cancer-derived cells." J Biol Chem 273(22): 14030-6.

12 da Costa, L. T., T. C. He, et al. (1999). "CDX2 is mutated in a colorectal cancer with normal APC/beta-catenin signaling." Oncogene 18(35): 5010-4.

13 Hinoi, T., P. C. Lucas, et al. (2002). "CDX2 regulates liver intestine-cadherin expression in normal and malignant colon epithelium and intestinal metaplasia." Gastroenterology 123(5): 1565-77.

14 Mazziotta RM, Borczuk AC, Alexis D et al. Differential expression, by immunohistochemsitry, of CDX2 transcription factor in various adenocarcinomas. Mod Pathol 2003;15:127A. [abstract] [These cases appear to be expanded upon in reference 30.]

15 Kaimaktchiev V, Firnhofer S, Sauter G et al. Selective staining of gastrointestinal adenocarcinoma by the homeobox intestinal differentiation factor CDX2. Mod Pathol 2003;15:123A. [abstract]

16 Furlanetto A, Orvieto E, Laurino L et al. Mod Pathol 2003;15:273A.

17 Li, M. K. and A. L. Folpe (2004). "CDX-2, a new marker for adenocarcinoma of gastrointestinal origin." Adv Anat Pathol 11(2): 101-5. [review]

18 Eda, A., H. Osawa, et al. (2003). "Aberrant expression of CDX2 in Barrett's epithelium and inflammatory esophageal mucosa." J Gastroenterol 38(1): 14-22.

19 Satoh, K., H. Mutoh, et al. (2002). "Aberrant expression of CDX2 in the gastric mucosa with and without intestinal metaplasia: effect of eradication of Helicobacter pylori." Helicobacter 7(3): 192-8.

20 Gaggero, G., S. Sola, et al. (2003). "[Expression of the cdx2 gene in benign intestinal-type mucinous ovarian tumors]." Pathologica 95(4): 185-91.

21 Yatabe, Y., T. Koga, et al. (2004). "CK20 expression, CDX2 expression, K-ras mutation, and goblet cell morphology in a subset of lung adenocarcinomas." J Pathol 203(2): 645-52.

22 Almeida, R., E. Silva, et al. (2003). "Expression of intestine-specific transcription factors, CDX1 and CDX2, in intestinal metaplasia and gastric carcinomas." J Pathol 199(1): 36-40.

23 Moskaluk, C. A., H. Zhang, et al. (2003). "Cdx2 protein expression in normal and malignant human tissues: an immunohistochemical survey using tissue microarrays." Mod Pathol 16(9): 913-9.

24 Hinoi, T., M. Tani, et al. (2001). "Loss of CDX2 expression and microsatellite instability are prominent features of large cell minimally differentiated carcinomas of the colon." Am J Pathol 159(6): 2239-48.

25 Osawa, H., H. Kita, et al. (2004). "Aberrant expression of CDX2 in the metaplastic epithelium and inflammatory mucosa of the gallbladder." Am J Surg Pathol 28(9): 1253-4.

26 Barbareschi, M., C. Roldo, et al. (2004). "CDX-2 homeobox gene product expression in neuroendocrine tumors: its role as a marker of intestinal neuroendocrine tumors." Am J Surg Pathol 28(9): 1169-76.

27 La Rosa, S., E. Rigoli, et al. (2004). "CDX2 as a marker of intestinal EC-cells and related well-differentiated endocrine tumors." Virchows Arch.

28 Groisman, G. M., M. Amar, et al. (2004). "Expression of the intestinal marker Cdx2 in the columnar-lined esophagus with and without intestinal (Barrett's) metaplasia." Mod Pathol 17(10): 1282-8.

29 Liu Q, Teh M, Ito K, et al. CDX2 expression is progressively decreased in human gastric intestinal metaplasia, dysplasia and cancer. Mod Pathol 2007; 20:1286-97

30 Mazziotta RM, Borczuk AC, Powell CA, et al. CDX2 immunostaining as a gastrointestinal marker: expression in lung carcinomas is a potential pitfall. Appl Immunohistochem Mol Morphol 2005; 13:55-60

49 Strickland-Marmol LB, Khoor A, Livingston SK, et al. Utility of tissue-specific transcription factors thyroid transcription factor 1 and Cdx2 in determining the primary site of metastatic adenocarcinomas to the brain. Arch Pathol Lab Med 2007; 131:1686-90 FULL TEXT

50 Dennis JL, Hvidsten TR, Wit EC, et al. Markers of adenocarcinoma characteristic of the site of origin: development of a diagnostic algorithm. Clin Cancer Res 2005; 11:3766-72 FULL TEXT

This page last revised 26.11.2008.