The p57(KIP2) protein (P57KIP2) is a potent tight-binding inhibitor of several G1 cyclin/Cdk complexes, and is a negative regulator of cell proliferation.
The p57KIP2 gene is paternally imprinted and maternally expressed, and the presence of its protein product serves as a surrogate marker for the nuclear maternal genome.
Because a complete HM (CHM) is the only type of conceptus lacking a maternal contribution, p57KIP2 immunostaining is correspondingly absent in this entity, whereas it is present in CHM mimics (partial mole).
Pathology
germline mutations in Beckwith-Wiedemann syndrome (BWS)(MIM.130650)
Immunochemistry
The p57KIP2 gene is paternally imprinted and maternally expressed; therefore, the positive staining of its protein indicates the presence of a functional maternal allele.
Because complete hydatidiform moles (CHMs) lack a maternal genome, p57KIP2 immunostaining is absent. (17904617)
p57KIP2 expression in molar pregnancy
- Negative p57KIP2 immunoreactivity (paternally imprinted, maternally expressed gene) is in perfect concordance with the androgenetic origin of molar pregnancies proven by DNA polymorphism. (15971478)
- p57KIP2 immunoreactivity, which can be performed in routine pathologic examinations, is a diagnostic tool to differentiate androgenetic complete moles from biparental conceptuses. (15971478)
References
Hoffner L, Dunn J, Esposito N, Macpherson T, Surti U. P57KIP2 immunostaining and molecular cytogenetics: combined approach aids in diagnosis of morphologically challenging cases with molar phenotype and in detecting androgenetic cell lines in mosaic/chimeric conceptions.Hum Pathol. 2008 Jan;39(1):63-72. PMID: 17904617
Maggiori MS, Peres LC. Morphological, immunohistochemical and chromosome in situ hybridization in the differential diagnosis of Hydatidiform Mole and Hydropic Abortion. Eur J Obstet Gynecol Reprod Biol. 2007 Dec;135(2):170-6. PMID: 17602823
Popiolek DA, Yee H, Mittal K, Chiriboga L, Prinz MK, Caragine TA, Budimlija ZM. Multiplex short tandem repeat DNA analysis confirms the accuracy of p57(KIP2) immunostaining in the diagnosis of complete hydatidiform mole. Hum Pathol. 2006 Nov;37(11):1426-34. PMID: 16949913
Romaguera RL, Rodriguez MM, Bruce JH, Zuluaga T, Viciana A, Penalver MA, Mehrdad N. Molar gestations and hydropic abortions differentiated by p57 immunostaining. Fetal Pediatr Pathol. 2004 Mar-Jun;23(2-3):181-90. PMID: 15768863
Jun SY, Ro JY, Kim KR. p57kip2 is useful in the classification and differential diagnosis of complete and partial hydatidiform moles. Histopathology. 2003 Jul;43(1):17-25. PMID: 12823708