Primary IGH translocations involving seven recurrent partner loci and oncogenes are present in about 40% of multiple myeloma tumors. Secondary IGH rearrangements, which occur in a smaller fraction of tumors, usually are complex structures, including insertions or translocations that can involve three chromosomes, and often with involvement of MYC. The main approach to detect IGH rearrangements is interphase – but sometimes metaphase – FISH strategies that use a telomeric variable region probe and a centromeric constant region/Eα enhancer or 3′ flanking probe to detect a separation of these two probes, or a fusion of these probes with probes located at nonrandom partner sites in the genome. We analyzed 18 myeloma cell lines for detection discrepancies among Vysis, Cytocell, and in-house IGH probe sets that hybridize with differing sequences in the IGH locus. There were no detection discrepancies for the three telomeric IGH probes, or for unrearranged IGH loci or primary IGH translocations using the centromeric IGH probes. However, the majority of complex IGH rearrangements had detection discrepancies among the three centromeric IGH probes.

A new ovarian near-diploid cell line, OVDM1, was derived from a highly aneuploid serous ovarian metastatic adenocarcinoma. A metastatic tumor was obtained from a 47-year-old Ashkenazi Jewish patient three years after the first surgery removed the primary tumor, both ovaries, and the remaining reproductive organs. OVDM1 was characterized by cell morphology, genotyping, tumorigenic assay, mycoplasma testing, spectral karyotyping (SKY), and molecular profiling of the whole genome by aCGH and gene expression microarray. Targeted sequencing of a panel of cancer-related genes was also performed. Hierarchical clustering of gene expression data clearly confirmed the ovarian origin of the cell line. OVDM1 has a near-diploid karyotype with a low-level aneuploidy, but samples of the original metastatic tumor were grossly aneuploid. A number of single nucleotide variations (SNVs)/mutations were detected in OVDM1 and the metastatic tumor samples. Some of them were cancer-related according to COSMIC and HGMD databases (no founder mutations in BRCA1 and BRCA2 have been found). A large number of focal copy number alterations (FCNAs) were detected, including homozygous deletions (HDs) targeting WWOX and GATA4. Progression of OVDM1 from early to late passages was accompanied by preservation of the near-diploid status, acquisition of only few additional large chromosomal rearrangements and more than 100 new small FCNAs. Most of newly acquired FCNAs seem to be related to localized but massive DNA fragmentation (chromothripsis-like rearrangements). Newly developed near-diploid OVDM1 cell line offers an opportunity to evaluate tumorigenesis pathways/events in a minor clone of metastatic ovarian adenocarcinoma as well as mechanisms of chromothripsis.

We have established and characterized a new ovarian cancer cell line derived from stage IV serous ovarian adenocarcinoma metastatic tissue from a 47 year old Ashkenazi Jewish patient. The patient developed ovarian cancer at age 44 and died of the disease at age 48. The tissue was obtained after an extensive secondary cytoreductive intraperitoneal surgery. Prior to the surgery the patient underwent primary cytoreduction followed by several systemic therapies with recurrences. A culture of the metastatic tissue was transfected with Simian Virus 40 Large T-Antigen and telomerase. The cell line has been in culture on and off during 3 years. The identity of the cell line was confirmed by Short Tandem Repeat genotyping on genomic DNA extracted from early and late passages as well as from frozen metastatic tissue. The cell line was further characterized by array-Comparative Genomic Hybridization and gene expression microarray; and by Spectral Karyotyping and Fluorescent In Situ Hybridization. The results of these analyses were compared, when appropriate, with those of frozen metastatic tissue. A low level of genetic instability was detected in the cell line, but the karyotypes seem to be near diploid and relatively stable, after several years of cultivation. We believe that this novel ovarian cancer cell line could contribute to the understanding of the molecular genetic basis of the disease in this advanced stage, and be representative of the tumors of a great number of patients that become resistant to the majority if not all known cancer therapies. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3265.