PNL2

This monoclonal antibody was originally generated against the human somatostatin receptor but shows no reactivity with the immunizing antigen. Rather, it appears to be a useful melanocytic marker, although the antigen has not yet been identified.

Immunohistochemical expression

Normal tissues are negative, apart from neutrophils and cutaneous melanocytes¹.

	Compound naevus	15/151	staining most prominent in junctional and superficial dermal melanocytes, similar to the pattern with HMB45
	Dysplastic naevus	15/151
	Blue naevus	2/21	homogenous diffuse positivity

		PNL2	Melan-A	HMB45	Tyrosinase	MitF	positive for all markers	negative for all markers	positive ONLY for PNL2
	Primary epithelioid melanoma	13/131
	Metastatic melanoma	33/38 (+:7, ++:3,+++:6,++++:17)1	31/38 (+:4, ++:7,+++:5,++++:15)1	29/38 (+:7, ++:5,+++:3,++++:14)1	35/38 (+:4, ++:9,+++:5,++++:17)1	32/38 (+:5, ++:4,+++:5,++++:18)1	26/381	1/381	2/381
	Desmoplastic melanoma	1/131	1/131	1/131	0/131	1/131
	Non-desmoplastic spindle cell melanoma	4/51
	Angiomyolipoma	10/101	18/18 (staining stronger and more extensive than for HMB45 and MitF)2	18/182	1/153	15/153

Staining is strongest in epithelioid melanomas¹.

	Lung	squamous carcinoma	0/11
		adenocarcinoma	0/11
	Breast	ductal carcinoma	0/51
		lobular carcinoma	0/51
	Colon, adenocarcinoma		0/11
	Renal clear cell carcinoma		0/51
	Ovarian carcinoma		0/51
	Transitional cell carcinoma		0/51
	Fibrosarcoma		0/41
	Leiomyosarcoma		0/31
	Liposarcoma		0/51
	Cellular dermatofibroma		0/51
	Neurofibroma		0/51
	Atypical fibroxanthoma		0/21
	Cellular neurothekeoma		0/21
	Granular cell tumour		0/11
	MPNST		1/13 (rare positive cells in one case with a focal rhabdomyosarcomatous component)1
	Melanotic Schwannoma		1/11
	AML		0/51
	CML		3/31

Diagnostic utility

• Another marker for melanoma

References

¹Busam KJ, Kucukgol D, Sato E, Frosina D, Teruya-Feldstein J,Jungbluth AA Immunohistochemical Analysis of Novel Monoclonal Antibody PNL2 and Comparison With Other Melanocyte Differentiation Markers. Am J Surg Pathol 2005; 29:400-406: this study was largely based on tissue micro-arrays.

²Jungbluth AA, Iversen K, Coplan K, et al. Expression of melanocyte-associated markers gp-100 and Melan-A/MART-1 in angiomyolipomas. An immunohistochemical and rt-PCR analysis. Virchows Arch 1999; 434:429-35

³Jungbluth AA, King R, Fisher DE, et al. Immunohistochemical and reverse transcription-polymerase chain reaction expression analysis of tyrosinase and microphthalmia-associated transcription factor in angiomyolipomas. Appl Immunohistochem Mol Morphol 2001; 9:29-34

This page last revised 15.3.2005.

©SMUHT/PW Bishop