Probes: Centromere 1 (1p11.1-q11.1) | Centromere 11 (11q12)
Antibody Marker: p57
Disease(s): Complete molar pregnancy vs. partial mole vs. abortus with hydropic changes
This test is available on a consult basis only.
Evaluation of products of conception to distinguish hydropic abortuses from complete or partial hydatidiform mole can be challenging. Molar Pregnancy Comprehensive Consultation offers a diagnostic solution where experienced, board-certified pathologists integrate the results of morphologic evaluation, p57 immunohistochemistry and Ploidy FISH for Molar Pregnancy to arrive at a final diagnosis.
Hydatiform moles (HM) are categorized as complete and partial and are usually considered the noninvasive form of gestational trophoblastic disease (GTD). While HM are typically deemed benign, they are premalignant and do have the potential to become malignant and invasive. Complete moles occur more frequently than partial moles and carry a higher risk of distant metastasis or choriocarcinoma. However, all molar pregnancies have the potential for persistent gestational trophoblastic neoplasia (GTN).
Ploidy FISH for Molar Pregnancy analyzes copy number of the chromosome 1 centromere and chromosome 11 centromere to assess triploidy vs. diploidy DNA content. Partial hydatidiform mole (PHM) shows triploid DNA content, complete hydatidiform mole (CHM) show predominately diploid DNA content, and normal non-molar placenta (NMP) can show diploid, triploid, or even tetraploid DNA content. Since morphologic features of hydatidiform moles (HMs) and hydropic abortus (HA) can often overlap, there is need for ancillary studies to help distinguish between the possibilities. The marker p57 is strongly paternally imprinted, being expressed from the maternal allele in most cases. Thus CHM, which contains paternal genes, shows absent or significantly reduced expression, serving as a reliable marker in addition to DNA ploidy testing for diagnosis.
- A formalin-fixed, paraffin-embedded (FFPE) tissue block is preferred specimen type
- FISH: One (1) unbaked, unstained slide for H&E staining (required) and four (4) positively charged unstained slides (all cut at 4-5 microns). IHC: One (1) unbaked, unstained slide for H&E staining (required) and two to three (2-3) positively charged unstained slides (all cut at 4-5 microns)
- Block and slide identifiers should be clearly written and match exactly with the specimen ID and specimen labeling as noted on the requisition.
Use cold pack for transport. Make sure cold pack is not in direct contact with specimen.