HER2 gene amplification in patients with breast cancer with equivocal IHC results.

Aims: Equivocal human epidermal growth factor receptor 2 protein (HER2) (2+) immunohistochemistry (IHC) is subject to significant interobserver variation and poses a challenge in obtaining a definitive positive or negative test result. This equivocal test result group accounts for approximately 15% of all tumours, and for optimal guidance of HER2 targeted therapy, a further analysis of quantification of gene copy number and amplification status is needed for patients with early or metastatic breast cancer.

Methods: 553 breast-cancer specimens with equivocal HER2 IHC(2+) test results were collected and subsequently centrally retested by chromogenic in situ hybridisation (CISH), and HER2 gene copy numbers per tumour cell nucleus were determined.

Multifocal myxoid liposarcoma--metastasis or second primary tumor?: a molecular biological analysis.

The classification of multifocal myxoid/round cell liposarcoma, which is defined as tumor presentation in at least two separate sites before manifestation in the lungs, as either metastasis or as a second primary tumor, has essential clinical consequences. Genetically, myxoid/round cell liposarcoma is characterized by t(12;16)(q13;p11) or t(12;22)(q13;q12), and various exon fusion transcripts are described with varying incidences, which permits their use as markers for clonality. Moreover, in solid tumors, analysis of loss of heterozygozity is valuable for clonality analysis.

Primary retroperitoneal myxoid/round cell liposarcoma is a nonexisting disease: an immunohistochemical and molecular biological analysis.

Almost all primary retroperitoneal liposarcomas can be classified as well-/dedifferentiated liposarcoma. Rarely, however, primary retroperitoneal liposarcoma is classified as myxoid/round cell liposarcoma, based on the presence of myxoid areas and vascular crow's feet pattern, which has resulted in a debate on the classification of liposarcoma in the retroperitoneum. Genetically, myxoid/round cell liposarcoma and well-/dedifferentiated liposarcoma are different diseases.