YUMM1.7 Syngeneic Model Overview

The YUMM1.7 syngeneic model is a genetically defined murine melanoma system derived from C57BL/6 mice as part of the Yale University Mouse Melanoma (YUMM) collection. This model was engineered to include key driver mutations commonly found in human cutaneous melanoma, involving the Braf, Pten, and Cdkn2a genes. Unlike spontaneously derived models such as B16, YUMM1.7 tumors arise from controlled oncogenic alterations that drive tumor initiation, progression, and immune evasion.

When implanted subcutaneously into C57BL/6 mice, YUMM1.7 cells form moderately growing, well-defined tumors with reproducible kinetics and measurable immune infiltration. The model’s defined genetic background and intact host immunity make it a powerful platform for translational studies investigating checkpoint blockade, tumor immune escape, and targeted therapy resistance. YUMM1.7 serves as a modern, molecularly relevant complement to traditional murine melanoma systems.

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Biological and Molecular Characteristics

The YUMM1.7 cell line originates from a genetically engineered mouse model carrying mutations in Braf, Pten, and Cdkn2a, which collectively activate the MAPK and PI3K-AKT signaling pathways. These pathways promote sustained proliferation, survival, and resistance to apoptosis while influencing immune modulation. Compared with the B16 melanoma family, YUMM1.7 tumors grow more slowly, display higher immunogenicity, and closely resemble the molecular features of human melanoma.

The model expresses melanoma-associated antigens such as gp100 and TRP-2 and exhibits moderate PD-L1 expression. The tumor microenvironment contains CD8-positive T cells, macrophages, and dendritic cells, along with suppressive myeloid populations. This balance between immunogenic and suppressive components makes YUMM1.7 a useful model for evaluating immune checkpoint inhibitors and targeted therapy combinations.

Parameter	Description
Host strain	C57BL/6 (female, 6–8 weeks)
Tumor origin	Genetically engineered melanoma (mutations in Braf, Pten, Cdkn2a)
Histological type	Poorly differentiated melanoma
Inoculation route	Subcutaneous or orthotopic (intradermal)
Tumor take rate	>90%
Doubling time	Approximately 4–6 days in vivo
Metastatic potential	Moderate; occasional lung metastases
Immunophenotype	Immunogenic; T-cell and macrophage infiltration
Common applications	Checkpoint blockade, targeted therapy, immunotherapy, tumor genomics

In Vivo Model Development and Tumorigenicity

YUMM1.7 tumors are established by subcutaneous inoculation of tumor cells into immunocompetent C57BL/6 mice, producing measurable growth within 7–10 days. Orthotopic implantation into the dermis or ear pinna can be used to better mimic the microenvironment of cutaneous melanoma. The model’s moderate growth rate allows for extended experimental windows, supporting longitudinal assessment of immune infiltration, cytokine signaling, and therapy response.

Because of its genetically defined background, YUMM1.7 is widely used to investigate targeted therapy resistance and adaptive immune mechanisms. It is particularly suited for combination studies involving MEK or BRAF inhibitors with PD-1 or CTLA-4 checkpoint blockade. The model’s reproducibility and genetic precision make it valuable for translational melanoma research where tumor–immune interactions and therapeutic synergy are of primary interest.

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Histopathology and Immunohistochemical Profile

Histologically, YUMM1.7 tumors consist of densely packed polygonal melanoma cells with high nuclear-to-cytoplasmic ratios and focal pigmentation. The tumors form compact sheets with limited necrosis and moderate vascularization. The supporting stroma contains fibroblasts, lymphocytes, and macrophages, creating an immune-active tumor microenvironment.

Immunohistochemical analysis reveals moderate Ki-67 expression consistent with steady proliferative activity. CD3 and CD8 staining confirm significant T-cell infiltration, while F4/80 and CD11b highlight macrophage and myeloid cell presence. PD-L1 expression is observed on tumor and immune cells and increases following interferon exposure or checkpoint inhibitor treatment. Activation of MAPK signaling is verified by phospho-ERK staining, and loss of PTEN protein correlates with constitutive AKT activation. These molecular and histological features underline YUMM1.7’s relevance as a defined and immunologically responsive melanoma model.

Preclinical Applications and Drug Response

The YUMM1.7 syngeneic model is a leading preclinical platform for evaluating both targeted and immune-based therapies against melanoma. It responds to immune checkpoint inhibitors targeting PD-1 and CTLA-4, with greater efficacy observed when combined with MAPK pathway inhibitors such as trametinib or dabrafenib. The model’s genetic alterations enable direct investigation of pathway inhibition, immune activation, and adaptive resistance.

YUMM1.7 has been applied in studies combining checkpoint blockade with cytokine therapy, radiation, or adoptive T-cell transfer. Its moderate immunogenicity and controlled tumor growth allow precise timing of interventions and detailed analysis of immune modulation. Because it accurately reflects the molecular landscape of human BRAF-mutant melanoma, YUMM1.7 remains a central model for translational immunotherapy and combination therapy research.

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To request the YUMM1.7 syngeneic model for your preclinical studies, please use the form below. A customized quote and additional model specifications will be provided upon inquiry.

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