p120 catenin

p120 catenin is encoded on chromosome 11q11. a-catenin and b-catenin bind to the intracellular domain of e-cadherin while p120 catenin binds e-cadherin at a juxta-membrane site. The complex stabilizes tight junctions. A deficiency of e-cadherin results in the intracytoplasmic accumulation of p120 catenin.

Immunohistochemical expression

Lobular carcinoma of the breast shows intracytoplasmic accumulation of p120 catenin while ductal carcinoma shows reduced membrane p120 catenin without cytoplasmic accumulation.

In gastric and colonic carcinoma, strong cytoplasmic p120 catenin is associated with dyscohesive infiltrative morphology.

Reference 1	cytoplasmic	cytoplasmic and membrane	membrane	weak	moderate	strong
Breast lobular carcinoma	64/64	0/64	0/64	0/64	0/64	0/64
Breast ductal carcinoma	0/62	0/62	62/62	0/62	0/62	62/62
Lung excluding small cell	0/23	8/23(1 weak, 3 moderate, 4 strong)	15/23(1 weak, 6 moderate, 8 strong)	2/23	9/23	12/23
Lung small cell carcinoma	8/33(weak)	12/33	5/33	19/33	5/33	1/33
Kidney	1/23(weak)	0/23	12/23	7/23	6/23	0/23
Bladder	0/62	8/62	52/62	7/62	38/62	15/62
Prostate	0/33	3/33	30/33	8/33	21/33	4/33
Testis	0/23	9/23	0/23	9/23	0/23	0/23
Ovary	2/79(2 weak)	42/79	35/79	6/79	65/79(36 "weak to moderate", 29 moderate)	8/79
Cervix	1/79(weak)	12/79	67/79	1/79	24/79	54/79
Pancreas	2/22(weak)	5/22	14/22	7/22	11/22	3/22
Thyroid	0/23	1/23	21/23	1/23	18/23	3/23
Head and neck	0/23	10/23	12/23	5/23	12/23	5/23
Throat	4/80(2 weak, 2 moderate, 1 strong)	24/80	51/80	10/80	46/80	23/80
Oesophagus	1/32 (weak)	13/32	16/32	8/32	20/32	2/32
Stomach	3/71(strong)	22/71	45/71	0/71	9/71	61/71
Colon	0/24	4/24	18/24	0/24	11/24	11/24
Rectum	9/60(strong)	15/60	36/60	6/60	36/60	18/60
Liver	0/23	5/23	16/23	4/23	11/23	6/23
Endocrine	7/39(6 weak, 1 moderate)	19/39	12/39	17/39	15/39	6/39

Diagnostic utility

Differentiation of lobular from ductal carcinoma of breast. Positivity of lobular carcinoma for p120 catenin may be easier to interpret than is negativity of epithelial cells for e-cadherin adjacent to positive myoepithelial cells.
Diagnosis of metastatic lobular carcinoma of breast by diffuse strong cytoplasmic staining. A panel of antibodies is needed to differentiate other dyscohesive tumours arising from stomach and colon.

References

1 Dabbs DJ, Bhargava R,Chivukula M. Lobular versus ductal breast neoplasms: the diagnostic utility of p120 catenin. Am J Surg Pathol 2007; 31:427-37

This page last revised 16.6.2007.