Hepatic mesenchymal hamartoma with translocation involving chromosome band 19q13.4: a recurrent abnormality.
ABSTRACT We report a case of mesenchymal hamartoma of the liver in an 8-month-old male child, in which the cytogenetic analysis revealed a balanced translocation, t(11;19)(q13;q13.4). This is the fifth description of a cytogenetic abnormality in mesenchymal hamartoma and is similar to the four cases reported previously in that one of the breakpoints involved chromosome band 19q13.4.
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ABSTRACT: Mesenchymal hamartoma of the liver (MHL) is an uncommon benign primary liver tumor that typically occurs in the pediatric population, although cases have been described in adults. MHL is sometimes associated with the highly malignant undifferentiated embryonal sarcoma (UES), and the synchronous or metachronous occurrence of MHL and UES suggests they share a common genetic link. Although the exact mechanism of tumorigenesis has not been identified, MHL cases harbor recurring chromosomal rearrangements involving 19q13. Design In order to provide more detail on the genetic events of MHL tumorigenesis, capture-based next generation sequencing (NGS) targeted to loci recently shown to be involved in a translocation in a case of UES arising in MHL (specifically, the MALAT1 gene on chromosome 11 and a gene poor region termed MHLB1 on chromosome 19) was performed on formalin fixed paraffin embedded tissue from seven cases of MHL. Chromosome rearrangements involving the MHLB1 locus were identified in three of the seven cases, including the translocation t(11,19)(q13.1;q13.42) involving the MALAT1 gene; the translocation t(2,19)(q31.1;q13.42) involving AK023515, an uncharacterized noncoding gene; and the inversion inv(19,19)(q13.42;q13.43) involving the PEG3 gene encoding a Kruppel-type zinc-finger protein. Rearrangements were exclusively identified in pediatric tumors. In each case, the presence of the rearrangement was confirmed by PCR and interphase FISH. Interphase FISH also demonstrated that the arrangements occur within the spindle cell component but not the epithelial components of the tumor. Since the MHLB1 locus contains a CpG-rich region whose methylation regulates C19MC miRNA genes, rearrangements that disrupt this region may contribute to MHL development through alteration of miRNA expression. The demonstration that the loose stromal cells harbor the rearrangements indicates that (some cases of) MHL are a neoplastic process due to a somatic genetic change and not a germline abnormality.Experimental and Molecular Pathology 10/2013; · 2.88 Impact Factor
Article: Hepatic cystic mesenchymal hamartomaMedical Journal Armed Forces India 11/2014;
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ABSTRACT: Abstract Recurrent genetic alterations found in hepatic mesenchymal hamartoma include either androgenetic-biparental mosaicism or chromosomal rearrangements involving chromosome 19q13.4, in the vicinity of the chromosome 19 microRNA cluster (C19MC). Abnormal activation of C19MC, which is subject to paternal imprinting and normally expressed only in placenta, could account for both genetic associations because androgenetic cells carry only paternal chromosomes. In this study, a 4.2-megabase deletion, involving the 5'-end of 19QMC, was detected in a sporadic mesenchymal hamartoma with a single nucleotide polymorphism hybridization array. Fluorescence-in-situ-hybridization studies showed that the deletion localized mesenchymal cells in the stroma of the hamartoma. Quantitative real-time polymerase chain reaction analysis of this tumor, 9 other sporadic hepatic mesenchymal hamartomas, and 3 hamartomas associated with androgenetic-biparental mosaicism demonstrated C19MC microRNA expression in all but 2 sporadic cases, with no significant expression in control liver. The findings support a pathogenetic model for mesenchymal hamartoma as a consequence of "ectopic" activation of C19MC in hepatic stroma, due to either chromosomal rearrangements or paternal uniparental disomy.Pediatric and Developmental Pathology 02/2014; 17(2). · 0.86 Impact Factor