Page 52 - SDIR5 Abstract book 21 12 2021.

POSTER PRESENTATIONS

P12

A novel triple negative lipid rich breast cancer (TN/LRBC) patient derived xenograft (PDX)

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Irida Papapostolou , Evangelia Sereti , Evangelia Bouloutsou , Vasileios Konteles ,Fani Koutsougianni ,
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Andromachi Lambrianidou , Antigoni Poultsidi , Maria Ioannou , Aspasia Tsezou , Konstantinos Dimas
1 Department of Pharmacology, Laboratory of Cytogenetics and Molecular Genetics, Department of Surgery,
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5 Department of Pathology, School of Medicine, University of Thessaly, Greece.
2 Department of Translational Medicine, Division of Urological Cancers, Lund University, Sweden

Background: Lipid-rich breast cancer (LRBC) is a rare subtype of breast cancer, highly metastatic and with
poor prognosis. It is reported to generally be negative for ER/PR receptors but highly positive for HER2
expression with triple negative (TN) cancers to be even rarer. Noteworthy, there are no models available
for studies on this rare type of cancer so far. Our aim was to establish and characterize a PDX from a patient
with TN/LRBC. Materials and methods: The model was developed in immunocompromised mice after direct
engraftment of tumor fragments surgically excised from the patient. The PDX was further evaluated
pharmacologically following patient’s schedule. Histological, karyotypic and NGS analysis were performed
for the first time for this type of cancer. Results: Pharmacological characterization revealed that the
xenograft responded well to cyclophosphamide and docetaxel, as was expected, but doxorubicin was found
to be highly toxic. As an alternative Caelyx® (stealth liposomal doxorubicin) was for the first time tested on
this type of breast cancer and found to be highly efficient with lower toxicity. Karyotyping revealed
polyploidy, while NGS analysis the presence of a pathogenic mutation in the MSH2 gene (c.482T> A, p.
Val161Asp) in both the patient and the xenograft. Data suggest that this mutation may be a driver
mutation. Conclusion: This is the first report on the development of a PDX for TN/ LRBC, a model that we
anticipate will be an extremely valuable tool towards developing novel treatments and understanding the
biology of this rare type of breast cancer.
Keywords: Triple negative lipid rich breast cancer, patient derived xenograft, liposomal doxorubicin
Acknowledgment: This research has been co-financed by the European Union and Greek national funds
through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call
RESEARCH – CREATE – INNOVATE (project code:T1EDK-01833)

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