Analysis of the PTCH1 signaling pathway in ovarian dermoids.

Dermoids belong to the group of developmental cysts and arise from germ cells. Studies on these tumors may therefore increase our understanding of normal germ cell development within different environments and cell lines derived from these lesions may also constitute an important vehicle for studying neoplasia and differentiation. Recently, we investigated the status of the PTCH1 locus in a large set of sporadic non-inflammatory, developmental cystic lesions. Our data showed allelic loss of microsatellite markers in close vicinity to the PTCH1 locus in both odontogenic keratocysts and dentigerous cysts as well as in ovarian dermoid cysts (ODC). In this study, we closely examined the status of the PTCH1 gene in ODCs. Although about 25% of cysts demonstrated LOH at the PTCH1 locus, no nonsense or missense mutations in the coding region of PTCH1 were detected in genomic DNA isolated from any of the ODCs examined by direct sequencing. Staining with PTCH1 and GLI1 antibodies showed that proteins were present in virtually all epithelial linings, with variable staining intensity not correlated with LOH and generally weaker for GLI1. However, cDNA microarray analysis performed on cell lines derived from ODCs did not show any significant alteration in the expression of the analyzed target genes of PTCH1 signaling in any of the cell lines examined, except for CyclinD1 (and several other genes generally not associated with PTCH1 signaling).

Role of the hedgehog/patched signaling pathway in oncogenesis: a new polymorphism in the PTCH gene in ovarian fibroma.

We compared the expression of target genes of Hedgehog/Patched signaling in ovarian fibromas and ovarian dermoids. We noted that high levels of SHH appear almost regularly, especially in dermoids, usually accompanied by increased expression of SMO. GLI overexpression does not coincide with that of PTCH. Loss of heterozygosity findings in the PTCH locus and increased expression of several genes in the pathway strongly suggest that the pathway is involved in both ovarian fibroma and dermoids.

Alterations in CDKN2A locus as potential indicator of melanoma predisposition in relatives of non-familial melanoma cases.

AIM: To examine constitutional alterations of CDKN2A/p16INK4A locus as a potential indicator of melanoma predisposition among the first-degree relatives of patients with malignant melanoma. METHOD: The study included eight families with a single member affected with melanoma. Members of the families were screened for allelic cosegregation with 9p21 region polymorphic markers IFNA, D9S126, and D9S104. The patient's tumors were screened for loss of heterozygosity (LOH) with the same markers, as well as for single strand conformational polymorphism (SSCP) variability of CDKN2A. In suspect cases, constitutional DNA was examined by SSCP and direct sequencing. RESULTS: LOH was detected in four cases, and SSCP indicated variability in at least one CDKN2A exon in these tumor samples. In three of four LOH cases, the remaining allele cosegregated within the family, which was interpreted as a preliminary indicator of potential genetic predisposition. In one of these three families, we found constitutional CDKN2A mutations in the patient and one of the relatives. In the second family, only the patient had the constitutionally altered gene, whereas no constitutional CDKN2A alterations were detected in the third family. All significant mutations were different and had not been reported before. CONCLUSION: We detected one case of melanoma predisposition among unaffected family members, which corresponded to statistical expectations for such a small number of screened families. Since constitutional mutations of CDKN2A exons have limited incidence, our stepwise approach seemed to be more informative and more affordable than straightforward CDKN2A sequencing of all subjects.