• All IHC stains will include a positive control tissue

• HLA-G staining has been reported in up to 100% (70-100%) of choriocarcinomas, placental site trophoblastic tumors, epithelioid trophoblastic tumors, placental site nodules, and exaggerated placental sites
• Non-trophoblastic tumors of GYN origin have been uniformly reported to be negative for HLA-G (one study ³ reported a case of cervical carcinoma which was focally positive for this marker)
• HLA-G, CD10 and HCG may be useful in a panel to recognize intermediate trophoblastic tumors. If the differential also includes cervical carcinoma, p16 should be added to this panel
• HLA-G has been reported to be associated with a shorter disease free survival in some breast, nasopharyngeal and thyroid carcinomas
• This marker has also been reported in a variety of other tumors, including malignant mesotheliomas, lung cancers, renal cell carcinomas, malignant mesotheliomas, lymphomas, etc, and has not been associated with a survival difference

Submit a formalin-fixed, paraffin-embedded tissue

Formalin-fixed, paraffin-embedded (FFPE) tissue block

FFPE tissue section mounted on a charged, unstained slide

Ambient (preferred)

• Unlabeled/mislabeled block
• Insufficient tissue
• Slides broken beyond repair

Immunohistochemical staining and microscopic examination

If requested, an interpretive report will be provided

Specifications

• HLA-G has been shown to be important for the escape of immunosurveillance (alloreactivity) by host T lymphocytes and NK cells
• In normal and molar placentas, expression of HLA-G is thought to play a role in maternal tolerance towards fetal tissue
• HLA-G appears to be exclusively expressed in intermediate trophoblast cells normal and molar pregnancies, and in choriocarcinomas
• Thus, HLA-G is a specific marker for intermediate trophoblast in gestational trophoblastic disease

Staining pattern

• Strong cytoplasmic staining

References

1. Singer, G, Kurman RJ et al: HLA-G immunoreactivity is specific for intermediate trophoblast in gestational trophoblastic disease and can serve as a useful marker in differential diagnosis. Am J Surg Pathol 26(7): 914-920, 2002.
2. Kleinberg L et al: Expression of HLA-G in malignant mesothelioma and clinically aggressive breast carcinoma. Virchows Arch (2006) 449: 31-39.
3. Kalhor N et al: Immunohistochemical studies of trophoblastic tumors. Am J Surg pathol 2009;33:633-638.