Islet 1, Isl1

Isl1 is a homeobox-related transcription factor that binds an enhancer within the insulin gene. Isl1 knockout mice lack pancreatic islets.

Immunohistochemical expression

Staining is nuclear.

Normal tissues: neurons of the adrenal medulla and dorsal root ganglia, neurons of the retina, pineal gland and some parts of the brain; islets cells of the pancreas.

	Endocrine tumours
			Isl1	TTF-1	CDX-2
	Pancreatic	primary	58/841	1/87(positivity in one insulinoma)1	18/871
	Pancreatic	metastatic	12/181	0/181	1/18(1 case weakly positive)1
	Lung	primary	5/311	16/311	0/311
	Ileum	primary	1/301	1/321	16/311
	Ileum	metastatic	0/171	0/191	11/181
	Appendix	primary	4/201	0/241	19/221
	Appendix	metastatic	0/41	0/41	3/41
	Stomach	primary	0/11	0/21	1/21
	Stomach	metastatic	0/11	0/11	1/11
	Duodenum	primary	1/21	0/21	1/21
	Duodenum	metastatic	2/21	0/21	2/21
	Colon	primary	0/21	0/21	0/21
	Colon	metastatic	0/21	0/21	1/21
	Rectum	primary	0/11	0/11	0/11

Diagnostic utility

Diagnosis of pancreatic endocrine tumours.

References

1 Schmitt AM, Riniker F, Anlauf M, et al. Islet 1 (Isl1) expression is a reliable marker for pancreatic endocrine tumors and their metastases. Am J Surg Pathol 2008; 32:420-5

This page last revised

10.5.2008.

5SMUHT/PW Bishop