The Active Tumor Vaccination in Combination With CDK4/6 Inhibitor Treatment: A Case Report.

BACKGROUND: Current standard treatment for metastatic breast cancer (MBC) involves cyclin-dependent kinase 4/6 (CDK4/6) inhibitors with endocrine therapy, showing potential in enhancing anti-tumor immune responses. CASE REPORT: This report details a clinical case of MBC where palbociclib was co-administered with letrozole. The integration of allogeneic tumor vaccination to this treatment led to heightened interferon-γ production, expansion of CD8+ and NK cell populations, and positive delayed-type hypersensitivity reactions, indicating successful development of anti-tumor immunity. The induced production of interferon-γ by tumor vaccination was associated with manageable modulation of sensitivity to palbociclib-letrozole therapy. Administration of the BioNTech/Pfizer Covid-19 vaccine compromised the anti-tumor immune response by reducing cytotoxic cell populations and increasing immunosuppressive cytokine production. The patient undergoing combined treatment achieved a progressive-free survival of 42 months. CONCLUSION: Incorporating active tumor vaccination with CDK4/6 inhibitor therapy presents a feasible approach for metastatic breast cancer. The precise regulation of the microenvironment emerges as a crucial factor and warrants careful consideration.

Loss of Heterozygosity of BRCA1/2 as a Predictive Marker for Talazoparib Response.

BACKGROUND/AIM: Tumor cell lines are essential tools in understanding the molecular mechanisms underlying cancer biology and therapeutic responses. Poly (ADP-ribose) polymerase inhibitors (PARPi) kill tumor cells harboring pathogenic mutations of BRCA DNA repair-associated genes 1/2 (BRCA1/2) and are approved to treat ovarian and metastatic breast cancer. Loss of heterozygosity (LOH) of the wild-type BRCA1/2 locus is suspected to increase cellular response to PARPi. To better elucidate the molecular mechanisms underlying PARPi sensitivity and resistance, this study assessed the responses of various pathogenic BRCA1/2-mutant cell lines to the PARPi talazoparib. MATERIALS AND METHODS: Mutant cell lines were extracted and cultured from four surgically resected, human breast cancer specimens with different pathogenic BRCA1/2, one normal breast specimen and one ovarian cancer specimen. Mutation analysis was performed on all cell lines using genomic DNA extraction and polymerase chain reaction. Following treatment with talazoparib, cell growth was assessed using tetrazolium salt and half-maximal inhibitory concentration values were determined. RESULTS: A partial correlation between different variants of pathogenic BRCA1/2 mutation and talazoparib susceptibility was found, with five of the cell lines exhibiting sensitivity to talazoparib. The most sensitive cell-line to talazoparib had LOH for BRCA1, while the breast cancer cell line harboring BRCA2 LOH was resistant to talazoparib. CONCLUSION: This study suggests that LOH does not necessarily correlate with PARPi efficacy. These results lay a foundation for future studies to utilize these novel cell lines to further elucidate the underlying molecular mechanisms of PARPi resistance and reveal new potential drug targets.

Autologous melanoma vaccine induces antitumor and self-reactive immune responses that affect patient survival and depend on MHC class II expression on vaccine cells.

PURPOSE: Autologous melanoma cells display a broad variety of tumor antigens and were used for treatment of American Joint Committee on Cancer stages III and IV melanoma as an adjuvant or active therapy. Survival data and immune response were evaluated in vaccinated patients. EXPERIMENTAL DESIGN: Forty-seven patients received 2,4-dinitrophenyl-conjugated autologous melanoma vaccine as an adjuvant (23 patients) or therapy (24 patients). CD4 and CD8 T-cell response in blood sampled before vaccination and after five or eight vaccine doses was evaluated against melanoma cells and autologous peripheral blood mononuclear cells using IFNgamma enzyme-linked immunospot. Serum levels of antilivin, an inhibitor of apoptosis, and anti-gp100 IgG were determined. RESULTS: The immunologic effect of the vaccine differed between the two groups of patients. In the adjuvant group, there was a significant increase in CD8 melanoma-reactive T cells (P = 0.035) after vaccination and an increase in antimelanoma CD4 T cells correlating with improved overall survival (P = 0.04). In the therapeutic group, there was no objective tumor regression; antimelanoma T-cell reactivity increased by a small amount, stayed the same, or in some cases decreased. In all patients, a significant increase was noted in CD4 T-cell reactivity against autologous peripheral blood mononuclear cells (P = 0.02), which did not affect survival. Increased antilivin IgG was associated with improved survival. Expression of MHC class II on melanoma cells was vital for the immunogenicity of the vaccine. CONCLUSION: Autologous melanoma cell vaccine is capable of inducing effective antimelanoma CD4 T-cell activity associated with improved survival. Patients with active metastatic disease generally displayed reduced immune response and gained little from active immunization.