Cancer Genetics and Epigenetics 2018, Vol.6, No.2, 13-18
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transmembrane protein expressed on the surface of T cells, mainly expressed on activated T cells. There are two
ligands, PD-L1 and PD-L2. PD-1 is expressed in infiltrating CD8 T cells. Also expressed in other fine cells of the
immune system, PD-1 ligand (PD-L1 or PD-L2) was up-regulated to block the anti-tumor immune response in
tumor microenvironment, resulting in reduced proliferation of activated CD8 T cells.
Some data showed that the expression of PD-L1, PD-L1 in TNBC was significantly higher in about 19% of
TNBC samples than in hormone-receptor-positive breast cancer.
4.1 Pembrolizumab (MK-3475)
At present, Pembrolizumab, a PD-1 antagonist, has been shown to be effective in many kinds of tumors. It can
specifically inhibit the binding of PD-1 and PD-L1, PD-L2 and restore the function of T cells. Has been approved
by the United States FDA for the treatment of melanoma, breast cancer research has also achieved some results.
Experiments have shown that patients with metastatic TNBC benefit permanently from pembrolizumab treatment
(Katz et al., 2018).
4.2 Atezolizumab (MPDL3280A)
MPDL3280A is a monoclonal antibody against PD-L1, which destroys the interaction between PD-L1 and PD-1
and restores the function of T cells. At present, the investigation have entered the stage of clinical trial, the
preliminary study shows that MPDL3280A treatment in metastatic TNBC women is durable and safe (McNamara
et al., 2014).
5 New Endocrine Therapy
Endocrine therapy is to inhibit the growth of tumor cells by regulating hormone levels and effects in vivo. Both
ER and PR were negative in triple negative breast cancer patients, so traditional endocrine therapy was not
effective for them.
5.1 Androgen receptor inhibitors
It showed that 10%~35% of patients with triple negative breast cancer expressed androgen receptor (AR). The
overexpression of AR, which often indicated poor prognosis. Blocking the expression of AR was a feasible
endocrine therapy for TNBC. Recent TBCRC011 phase II clinical trials showed that antiandrogen receptor
inhibitors had a clinical benefit for 19% of patients compared with Carous (Gucalp et al., 2013; McNamara et al.,
2014).
5.2 Others
Endocrine therapy for triple negative breast cancer also includes the treatment of gonadotropin releasing hormone
and growth hormone releasing hormone. However, the current research progress of them is not enough.
6 Prospect
As a unique subtype of breast cancer, the treatment of triple negative breast cancer has not been able to meet the
survival requirements of patients. Although a large number of related clinical trials have been carried out, no
targeted treatment has been found. The current clinical treatment is still in the exploratory stage. Targeted therapy
is still the most promising way to improve the survival of patients in the short term. Immunotherapy is expected to
become an innovation in the field of triple negative breast cancer treatment after surgery, chemotherapy,
radiotherapy and molecular targeted therapy. The research of new endocrine therapy is being carried out step by
step. It is believed that the treatment level of triple negative breast cancer will make a great leap forward in the
near future.
Authors’ contributions
JYZ wrote this manuscript. DWZ revised the manuscript. All authors read and approved the final manuscript.
Acknowledgements
This work was supported by the Heilongjiang scientific research project (grants 201810).
