TY  - JOUR
A1  - Livingstone, E.
A1  - Zaremba, A.
A1  - Horn, S.
A1  - Ugurel, S.
A1  - Casalini, B.
A1  - Schlaak, M.
A1  - Hassel, J.C.
A1  - Herbst, R.
A1  - Utikal, J.S.
A1  - Weide, B.
A1  - Gutzmer, R.
A1  - Meier, F.
A1  - Koelsche, C.
A1  - Hadaschik, E.
A1  - Sucker, A.
A1  - Reis, H.
A1  - Merkelbach‐Bruse, S.
A1  - Siewert, M.
A1  - Sahm, F.
A1  - von Deimling, A.
A1  - Cosgarea, I.
A1  - Zimmer, L.
A1  - Schadendorf, D.
A1  - Schilling, B.
A1  - Griewank, K.G.
T1  - GNAQ and GNA11 mutant nonuveal melanoma: a subtype distinct from both cutaneous and uveal melanoma
JF  - British Journal of Dermatology
N2  - Background
GNAQ and GNA11 mutant nonuveal melanoma represent a poorly characterized rare subgroup of melanoma with a gene mutation profile similar to uveal melanoma.

Objectives
To characterize these tumours in terms of clinical behaviour and genetic characteristics.

Methods
Patients with nonuveal GNAQ/11 mutated melanoma were identified from the prospective multicentre tumour tissue registry ADOREG, Tissue Registry in Melanoma (TRIM) and additional cooperating skin cancer centres. Extensive data on patient, tumour and treatment characteristics were collected retrospectively. Targeted sequencing was used to determine tumour mutational burden. Immunohistochemistry staining was performed for programmed death‐ligand 1 and BRCA1‐associated protein (BAP)1. Existing whole‐exome cutaneous and uveal melanoma data were analysed for mutation type and burden.

Results
We identified 18 patients with metastatic GNAQ/11 mutant nonuveal melanoma. Tumours had a lower tumour mutational burden and fewer ultraviolet signature mutations than cutaneous melanomas. In addition to GNAQ and GNA11 mutations (nine each), six splicing factor 3b subunit 1 (SF3B1), three eukaryotic translation initiation factor 1A X‐linked (EIF1AX) and four BAP1 mutations were detected. In contrast to uveal melanoma, GNAQ/11 mutant nonuveal melanomas frequently metastasized lymphatically and concurrent EIF1AX, SF3B1 and BAP1 mutations showed no apparent association with patient prognosis. Objective response to immunotherapy was poor with only one partial response observed in 10 treated patients (10%).

Conclusions
Our findings suggest that GNAQ/11 mutant nonuveal melanomas are a subtype of melanoma that is both clinically and genetically distinct from cutaneous and uveal melanoma. As they respond poorly to available treatment regimens, novel effective therapeutic approaches for affected patients are urgently needed.

What is already known about this topic?
The rare occurrence of GNAQ/11 mutations in nonuveal melanoma has been documented.
GNAQ/11 mutant nonuveal melanomas also harbour genetic alterations in EIF1AX, SF3B1 and BAP1 that are of prognostic relevance in uveal melanoma.

What does this study add?
GNAQ/11 mutant nonuveal melanomas show metastatic spread reminiscent of cutaneous melanoma, but not uveal melanoma.
GNAQ/11 mutant nonuveal melanomas have a low tumour mutational burden that is higher than uveal melanoma, but lower than cutaneous melanoma.

What is the translational message?
Primary GNAQ/11 mutant nonuveal melanomas are a subtype of melanoma that is clinically and genetically distinct from both cutaneous and uveal melanoma.
As metastatic GNAQ/11 mutant nonuveal melanomas respond poorly to available systemic therapies, including immune checkpoint inhibition, novel therapeutic approaches for these tumours are urgently needed.
KW  - melanoma
KW  - GNAQ
KW  - GNA11
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-215434
VL  - 183
IS  - 5
SP  - 928
EP  - 939
ER  - 
TY  - JOUR
A1  - Diessner, J.
A1  - Bruttel, V.
A1  - Stein, R. G.
A1  - Horn, E.
A1  - Häusler, S. F. M.
A1  - Dietl, J.
A1  - Hönig, A.
A1  - Wischhusen, J.
T1  - Targeting of preexisting and induced breast cancer stem cells with trastuzumab and trastuzumab emtansine (T-DM1)
JF  - Cell Death & Disease
N2  - The antibody trastuzumab (Herceptin) has substantially improved overall survival for patients with aggressive HER2-positive breast cancer. However, about 70% of all treated patients will experience relapse or disease progression. This may be related to an insufficient targeting of the CD44(high)CD24(low) breast cancer stem cell subset, which is not only highly resistant to chemotherapy and radiotherapy but also a poor target for trastuzumab due to low HER2 surface expression. Hence, we explored whether the new antibody-drug conjugate T-DM1, which consists of the potent chemotherapeutic DM1 coupled to trastuzumab, could improve the targeting of these tumor-initiating or metastasis-initiating cells. To this aim, primary HER2-overexpressing tumor cells as well as HER2-positive and HER2-negative breast cancer cell lines were treated with T-DM1, and effects on survival, colony formation, gene and protein expression as well as antibody internalization were assessed. This revealed that CD44(high)CD24(low)HER2(low) stem cell-like breast cancer cells show high endocytic activity and are thus particularly sensitive towards the antibody-drug conjugate T-DM1. Consequently, preexisting CD44(high)CD24(low) cancer stem cells were depleted by concentrations of T-DM1 that did not affect the bulk of the tumor cells. Likewise, colony formation was efficiently suppressed. Moreover, when tumor cells were cocultured with natural killer cells, antibody-dependent cell-mediated cytotoxicity was enhanced, and EMT-mediated induction of stem cell-like properties was prevented in differentiated tumor cells. Thus our study reveals an unanticipated targeting of stem cell-like breast cancer cells by T-DM1 that may contribute to the clinical efficacy of this recently approved antibody-drug conjugate.
KW  - tumor stem cells
KW  - breast cancer
KW  - T-DM1
KW  - HER2
KW  - argeted therapy
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-119884
SN  - 2041-4889
VL  - 5
ER  -