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Homozygous deletions scanning in tumor cell lines detects previously unsuspected loci
Pascal Pineau1, Agnès Marchio, Emilie Cordina
1Unité de Recombinaison et Expression Génétique, INSERM, Département de Médecine Moléculaire, Institut Pasteur, Paris, France. ppineau@pasteur.fr
Abstract:
High rates of loss of heterozygosity commonly affect multiple chromosomes in individual tumor types, yet the number of known tumor suppressor genes (TSGs) systematically mutated in the corresponding tumors is usually low. The search for homozygously deleted genome segments in tumor samples or cell lines has become a method of choice to identify major TSGs or to reveal their influence on the development of a given tumor type. Here, we report a detailed homozygous deletion (HD) profiling for 246 critical loci on a panel of 89 tumor cell lines containing significant subsets of lung, ovarian and head and neck squamous cell carcinomas. We found a total of 53 HDs affecting 17 loci. The major target for HDs was p16-INK4A/p14-ARF (23/89, 26% of cases). Among the remaining alterations, HDs affecting TP73 or telomeric markers have never been previously described, whereas other HDs represent the first examples associating lesions of certain TSGs with a given tumor type (NF2 in lung and ovarian cells, STK11 in HELA cells). Overall, tumor cell lines established from ovarian or lung carcinomas displayed a surprising diversity of loci targeted by HDs with 7 and 6 loci involved, respectively. Our data suggest that, beside allelotyping or transcriptome/proteome studies, extensive HD profiling represents a promising approach for the detection of hitherto not implicated signalling pathways of tumorigenesis.
Insights
Homozygous deletion (HD) profiling identified new tumor suppressor genes (TSGs) in lung and ovarian cancers. This method reveals novel genetic alterations crucial for tumorigenesis, expanding our understanding of cancer development.
Area of Science:
- Oncology
- Genetics
- Molecular Biology
Background:
- Loss of heterozygosity (LOH) is common in tumors, but known tumor suppressor genes (TSGs) are often sparsely mutated.
- Identifying TSGs is crucial for understanding tumor development and therapeutic strategies.
Purpose of the Study:
- To perform comprehensive homozygous deletion (HD) profiling on a large panel of tumor cell lines.
- To identify novel TSGs and pathways involved in lung, ovarian, and head and neck squamous cell carcinomas.
Main Methods:
- HD profiling was conducted on 89 tumor cell lines, targeting 246 critical loci.
- Analysis focused on identifying homozygous deletions across various cancer types.
Main Results:
- A total of 53 HDs were identified across 17 loci.
- The p16-INK4A/p14-ARF locus was the most frequent HD target (26% of cases).
- Novel HDs were found for TP73, telomeric markers, NF2 in lung/ovarian cells, and STK11 in HeLa cells.
Conclusions:
- Extensive HD profiling is a valuable method for discovering new TSGs and tumorigenesis pathways.
- Tumor cell lines from ovarian and lung carcinomas show diverse HD profiles.
- HD profiling complements other omics approaches for comprehensive cancer research.