Soft Tissues: Biphasic svial sarcoma with t(X;20)(p11;q13) SS18L1/SSX1

2007-04-01   Clelia Tiziana Storlazzi , Fredrik Mertens 

1.Department of Genetics, Microbiology, University of Bari, Via Amendola 165\/A, 70126 Bari, Italy (CTS);, Dept of Clinical Genetics, Lund University Hospital, SE-221 85 Lund, Sweden (FM).

Clinics and Pathology

Pathology

The excised tumor consisted of a single 3-cm nodulus with relatively well-defined borders and a grey cut surface. No necrosis was seen. In histological sections stained with H and E, the tumor was mainly composed of uniform, closely packed spindle cells, with a high nuclear/cytoplasmic ratio and finely dispersed chromatin. The tumor cells were arranged in fascicles and whorls, with small foci of calcification. The mitotic activity was low. In addition, small and irregular glandular formations lined by flattened cuboidal cells were noted in the peripheral parts of the tumor, supporting the diagnosis of biphasic synovial sarcoma. These cells, as well as many spindle cells, expressed cytokeratins and epithelial membrane antigen (EMA).

Treatment

The patient was given postoperative chemo- and radiotherapy.

Evolution

Four months postoperatively, the patient is alive without any sign of local recurrence or metastatic disease.

Cytogenetics

Atlas Image
Top: Partial karyotype showing G-banded chromosomes X, 18, 20 and markers 1 and 2.
Bottom: FISH cohybridization using a pool of RP11-552E4 and RP11-344N17 (red), RP5-1005F21 (purple), and pZ20 (green) as probes for chromosomes X, 20, and the two markers. The results on mar2 are shown as a three-color image (left), as well as separately for each of the probes (right).

Cytogenetics morphological

48,XY,+mar1,+mar2[5]/47,idem,dic(19;22)(q13;q13)[3] .

Cytogenetics molecular

With a pool of SSX BAC probes, one and two signals were seen on mar1 and mar2, respectively. On the latter marker chromosome, one of the signals co-localized with the signal from RP5-1005F21, suggesting the presence of a fusion gene between SS18L1 and one of the SSX genes.

Probes

RP5-1005F21 (SS18L1), RP11-552E4 and RP11-344N17 (pool of SSX genes).

Genes Involved and Proteins

Gene name

SS18L1 (synovial sarcoma translocation gene on chromosome 18-like 1)

Location

20q13.33

Note

Paralogous gene to SS18 (18q11.2).

Dna rna description

Genomic (chr20:60,169,869-60,189,352). Transcript of 4566 bp (NM_198935).

Gene name

SSX1 (SSX family member 1)

Location

Xp11.23

Note

Gene belonging to the SSX gene family.

Dna rna description

Genomic (chrX:47,999,741-48,011,823). Transcript of 1271 bp (NM_005635).

Protein description

188 amino acids (Q16384).

Result of the chromosomal anomaly

Description

Nucleotide 1216 (exon 10) of SS18L1 (Accession Number XM_037202) was fused in-frame with nt 422 (exon 6) of SSX1 (Accession Number X86174).

Bibliography

Pubmed IDLast YearTitleAuthors
126960682003A novel fusion gene, SS18L1/SSX1, in synovial sarcoma.Storlazzi CT et al

External Links

Citation

Clelia Tiziana Storlazzi ; Fredrik Mertens

Soft Tissues: Biphasic svial sarcoma with t(X;20)(p11;q13) SS18L1/SSX1

Atlas Genet Cytogenet Oncol Haematol. 2007-04-01

Online version: http://atlasgeneticsoncology.org/solid-tumor/5464/soft-tissues-biphasic-svial-sarcoma-with-t(x;20)(p11;q13)-ss18l1-ssx1