Apo D

Apo D is a 33 kDa glycoprotein component of plasma high-density lipoprotein. Its gene is at 3q26.2: it is not involved in the t(17;22) translocation of dermatofibrosarcoma protuberans.

Immunohistochemical expression

Soft tissue tumours¹:

		weak positivity (light staining of more than 20% of tumour cells but dark staining of less than 50% of tumour cells)	strong positivity (dark staining of more than 50% of tumour cells)
	Dermatofibrosarcoma protuberans	2/10	7/10
	Plaque stage dermatofibrosarcoma protuberans	3/3
	Myxoid dermatofibrosarcoma protuberans	1/1
	Dermatofibrosarcoma protuberans with sarcomatous transformation	3/6
	Bednar tumour	3/3
	Giant cell fibroblastoma	2/3
	Usual fibrous histiocytoma	0/16
	Angiomatoid fibrous histiocytoma	0/3
	Epithelioid fibrous histiocytoma	0/2
	Plexiform fibrous histiocytoma	0/2
	Atypical fibrous histiocytoma	0/4 (only scattered atypical (monster) cells stained)
	Aneurysmal fibrous histiocytoma	0/1
	Alveolar soft part sarcoma	0/2	2/2
	Angiosarcoma	4/14	3/14
	Atypical lipomatous tumour	8/34	2/34
	Carcinosarcoma	1/7	0/7
	Endometrial stromal sarcoma	0/9	2/9
	Eosinophilic granuloma	1/1	0/1
	Ewing's sarcoma/PNET	2/10	1/10
	Fibromatosis	1/18	0/18
	Fibroxanthoma	3/4	0/4
	Glomus tumour	0/5	3/5
	Granular cell tumour	4/11	4/11
	Haemangioblastoma	3/10	0/10
	Inflammatory pseudotumour	1/2	0/2
	Leiomyosarcoma	4/37	0/37
	Lymphangioma	1/2	0/2
	Malignant fibrous histiocytoma	19/53	1/53
	Osteosarcoma	2/14	1/14
	Paraganglioma	1/1	0/1
	Neurofibroma	6/8
	Peripheral nerve sheath tumour, benign	0/3	1/3
	Peripheral nerve sheath tumour, malignant	1/5	2/5
	Rhabdomyoma	1/1	0/1
	Rhabdomyosarcoma	1/13	1/13
	Solitary fibrous tumour	4/11	0/11
	Synovial sarcoma	4/56	0/56
	Tenosynovial giant cell tumour	8/9	1/9
	Angiomyxoma	0/1
	Chondrosarcoma	0/5
	Clear cell sarcoma	0/3
	Desmoplastic small round cell tumour	0/4
	Elastofibroma	0/1
	Embryonal sarcoma	0/1
	Epithelioid sarcoma	0/2
	Fasciitis	0/7
	Fibroma/fibroblastoma	0/3
	Fibromyxoid sarcoma	0/1
	Fibrosarcoma	0/4
	GIST	0/36
	Glomangioma	0/4
	Haemangioendothelioma	0/10
	Haemangioma	0/2
	Haemangiopericytoma	0/1
	Hibernoma	0/2
	Kaposi's sarcoma	0/3
	Leiomyoma	0/8
	Lipoblastomatosis	0/3
	Masson's lesion	0/1
	Myofibrosarcoma	0/1
	Myxofibrosarcoma	0/1
	Myxoma	0/8
	Neuroblastoma	0/1
Osteosarcoma	0/14
Rosai-Dorfmann disease	0/1
Sarcoma NOS	0/10

Histiocyte-like cells within various tumours may be positive.

CNS tumours²:

	Pilocytic astrocytoma	10/13
	infiltrating astrocytomas	0/21
	gangliogliomas	9/14
	subependymal giant cell astrocytomas	4/5
	pleomorphic xanthoastrocytomas	1/1

Apo D expression may be a good prognostic indicator in breast⁴ and ovarian³ carcinomas.

Diagnostic utility

Differentiation of dermatofibrosarcoma protuberans (positive) from fibrous histiocytoma (negative)¹.

Differentiation of pilocytic astrocytoma (positive) from infiltrating astrocytoma (negative)².

References

¹West, R. B., J. Harvell, et al. (2004). "Apo D in soft tissue tumors: a novel marker for dermatofibrosarcoma protuberans." Am J Surg Pathol 28(8): 1063-9. Note: all TMA immunostain results are available on line.

²Hunter, S., A. Young, et al. (2002). "Differential expression between pilocytic and anaplastic astrocytomas: identification of apolipoprotein D as a marker for low-grade, non-infiltrating primary CNS neoplasms." J Neuropathol Exp Neurol 61(3): 275-81.

³Vazquez, J., L. Gonzalez, et al. (2000). "Expression and clinical significance of apolipoprotein D in epithelial ovarian carcinomas." Gynecol Oncol 76(3): 340-7.

⁴Diez-Itza, I., F. Vizoso, et al. (1994). "Expression and prognostic significance of apolipoprotein D in breast cancer." Am J Pathol 144(2): 310-20.

This page last revised 11.9.2004.

©SMUHT/PW Bishop