ABSTRACT
Pulmonary chondroid hamartomas (PCHs) are benign mesenchymal tumors that often are characterized by specific chromosomal aberrations. Herein we report our cytogenetic and molecular cytogenetic (FISH) studies on 191 PCHs, including 48 previously published cases. In this series, 134/191 PCHs (70.2%) showed either abnormalities of chromosomal bands 6p21 (21 tumors), 12q14-15 (95 tumors), or had other abnormalities (18 tumors). Two tumors had a 6p21 aberration together with a 12q14-15 aberration. The most frequent translocations were t(12;14)(q15;q24) (19 cases) and t(6;14)(p21. 3;q24) (18 cases), both in either simple or complex form. By FISH with cosmids spanning the gene encoding the high-mobility-group protein HMGIC, we were able to show a rearrangement within or close to HMGIC in all tumors with 12q14-15 abnormalities tested, in 11 tumors with an apparently normal karyotype, and in 4 tumors with complex abnormalities without cytogenetically visible alterations of chromosomes 12. Rearrangements of HMGIY or its immediate surroundings were shown for 21 cases with 6p21 aberrations and three cases with other chromosomal abnormalities but without cytogenetically visible alterations of chromosomes 6. Genes Chromosomes Cancer 26:125-133, 1999.
Subject(s)
Hamartoma/genetics , High Mobility Group Proteins/genetics , Lung Neoplasms/genetics , Neoplasm Proteins/genetics , Transcription Factors/genetics , Translocation, Genetic/genetics , Adolescent , Adult , Aged , Chromosomes, Human, Pair 12/genetics , Chromosomes, Human, Pair 6/genetics , HMGA1a Protein , Humans , In Situ Hybridization, Fluorescence , Karyotyping , Male , Middle AgedABSTRACT
Pulmonary chondroid hamartomas (PCH) are benign tumors of the lung characterized by a more or less high degree of mesenchymal metaplasia. In our series we investigated 30 PCH by a combination of cytogenetic and molecular methods. 18 tumors (60%) had cytogenetically detectable aberrations involving either 12q14-15 or 6p21 with a clear predominance of chromosomal abnormalities involving 12q14-15 (15 tumors). As in subgroups of pleomorphic adenomas of the salivary glands, leiomyomas of the uterus, and lipomas with 12q14-15 abnormalities the HMGI-C gene is frequently rearranged we tested PCH with either 12q14-15 abnormalities or normal karyotype by FISH and 3' RACE experiments for rearrangements of HMGI-C. Rearrangements were found in all cases with chromosomal 12q14-15 abnormalities and further six cases with an apparently normal karyotype. By the combination of cytogenetics with molecular techniques the percentage of cases with intragenic rearrangements of HMGI-C or rearrangements of its immediate surrounding was thus increased to 70% (21/30 cases). Considering all types of aberrations within this series 80% (24/30) of all PCH were aberrant. This is the first report on a combined molecular and cytogenetic analysis of a large series of pulmonary chondroid hamartomas indicating that rearrangements of HMGI-C, a member of the high mobility group protein gene family, are the leading molecular events in the genesis of PCH.
Subject(s)
Chromosome Aberrations , Chromosome Disorders , Chromosomes, Human, Pair 12 , Gene Rearrangement , Hamartoma/genetics , Lung/abnormalities , Adult , Aged , Base Sequence , Chromosome Banding , Chromosome Mapping , DNA Primers , Exons , Female , HMGA2 Protein , Hamartoma/pathology , High Mobility Group Proteins/genetics , Humans , In Situ Hybridization, Fluorescence , Karyotyping , Lung/pathology , Male , Middle Aged , Molecular Sequence Data , Phosphoproteins/genetics , Polymerase Chain ReactionABSTRACT
Chromosomal aberrations involving the chromosomal breakpoint region 12q14-15 are frequently seen in a variety of mesenchymal tumors as uterine leiomyomas, lipomas, myxoid liposarcomas, enchondromas, or hemangiopericytomas. Therefore, this breakpoint region seems to be one of the most frequent chromosomal abnormality associated with the initiation of human mesenchymal neoplasms. To narrow down the breakpoint region on a molecular level in cells of three pulmonary chondroid hamartomas with 12q14-15 aberrations, we performed fluorescence in situ hybridization analysis with different cosmid clones originating from a YAC and cosmid contig overspanning parts of the region 12q14-15. We were able to narrow down the breakpoint to a region of 175 kb belonging to an area designated multiple aberration region because it also includes the breakpoints of leiomyomas, lipomas, and pleomorphic adenomas with 12q14-15 abnormalities. Our molecular and cytogenetic data suggest that hamartomas of the lung molecularly belong to the benign group of mesenchymal tumors showing multiple aberration region involvement.
