TTF-1 and c-MYC-defined Phenotypes of Large Cell Neuroendocrine Carcinoma and Delta-like Protein 3 Expression for Treatment Selection

The standard treatment regimen has not yet been established for advanced pulmonary large cell neuroendocrine carcinoma (LCNEC) because of its rarity. LCNEC can be subdivided into 2 mutually exclusive molecular subgroups: STK11/KEAP1 and TP53 mutated with high neuroendocrine expression and transcriptional profile of ASCL1high/DLL3high/NOTCHlow (non-small cell lung carcinoma, NSCLC-like) or RB1 and TP53 mutated with reduced neuroendocrine markers and transcriptional pattern of ASCL1low/DLL3low/NOTCHhigh (small cell lung cancer, SCLC-like). Model-based clustering shows that SCLC has subdivided into 2 major proteomic subsets defined by either TTF-1high/c-MYClow or TTF-1low/c-MYChigh, which may correspond to 2 mutually exclusive molecular subgroups: NSCLC-like or SCLC-like, respectively. We herein investigated whether TTF-1 and c-MYC could be applied to LCNEC to identify distinct subsets immunohistochemically and assessed DLL3 expression in these subsets. The protein expression profile may be useful to select patients for potential efficacy of targeted therapies including aurora kinase inhibitors for MYC alterations or anti-DLL3 antibody-drug conjugates. TTF-1 and c-MYC expression was mutually exclusive in 25 of 27 (93%) cases; TTF-1+/c-MYC- in 10, TTF-1-/c-MYC+ in 15, and TTF-1+/c-MYC+ in 2. DLL3 expression was seen in 15 of 27 cases (56%). All 12 TTF-1+ LCNEC cases were positive for DLL3. Three of 15 (20%) TTF-1-/c-MYC+ cases showed DLL3 positivity. LCNEC could be separated into 2 subsets proteomically defined by TTF-1 and c-MYC expression, which may be suitable to guide treatment selection including aurora kinase inhibitors for c-MYC+ cases. TTF-1 positivity can serve as a surrogate marker for DLL3, but caution is necessary as 20% of TTF-1- cases showed DLL3 positivity.

Activation of cyclin D1-related kinase in human lung adenocarcinoma

Cyclin D1 gene amplification is an important event in many cancers, but it is rarely found in non-small-cell lung cancer (NSCLC). This study was conducted in an attempt to clarify any other mechanisms related to cyclin D1 involvement in the malignant transformation of NSCLC, and we clearly showed for the first time that cyclin D1-related kinases are activated in NSCLC, especially in adenocarcinoma but not in squamous cell carcinoma. The results of this study strongly suggest that enhanced cyclin D1-related kinase activity could contribute to a progression of adenocarcinoma in NSCLC.

Cytotoxic T lymphocytes that recognize decameric peptide sequences of retinoblastoma binding protein 1 (RBP-1) associated with human breast cancer

Retinoblastoma binding protein 1 (RBP-1) is a 143-kDa nuclear phosphoprotein that promotes cell growth by inhibiting the product of retinoblastoma tumour suppressor gene (pRB). We recently found that RBP-1 contains KASIFLK, a heptameric peptide (250-256) recognized by human antibodies and overexpressed by breast cancer cells. In the present study, we demonstrate that human T-cells stimulated with RBP-1 decameric peptides containing KASIFLK can kill human breast cancer cells. These decamers, GLQKASIFLK (247-256) and KASIFLKTRV (250-259), have anchor motifs for both HLA-A2 and HLA-A3. Peripheral blood lymphocytes from 41 normal donors were stimulated by these peptides in culture media containing 15 IU ml(-1) interleukin-2, 25 IU ml(-1) interleukin-7 and 500 IU ml(-1) granulocyte-macrophage colony-stimulating factor. Cytotoxic activity of the T-cells was assessed against autologous B lymphoblastoid cells pulsed with each peptide. Stimulation by GLQKASIFLK generated specific cytotoxic T lymphocyte (CTL) lines from HLA-A2, A3 donors, HLA-A2 donors and HLA-A3 donors. Stimulation with KASIFLKTRV generated specific CTL lines from HLA-A2 donors. No HLA-A2-, A3 CTL line showed specific cytotoxicity against these target cells. These CTL lines were also cytotoxic against HLA-A2 and HLA-A3 breast cancer cells but not against normal fibroblastoid cell lines, normal epidermal cell lines, or a melanoma cell line. RBP-1 peptide antigens may be of clinical significance as a potential peptide vaccine against human breast cancer.