Systemic spread is an early step in breast cancer.

It is widely accepted that metastasis is a late event in cancer progression. Here, however, we show that tumor cells can disseminate systemically from earliest epithelial alterations in HER-2 and PyMT transgenic mice and from ductal carcinoma in situ in women. Wild-type mice transplanted with single premalignant HER-2 transgenic glands displayed disseminated tumor cells and micrometastasis in bone marrow and lungs. The number of disseminated cancer cells and their karyotypic abnormalities were similar for small and large tumors in patients and mouse models. When activated by bone marrow transplantation into wild-type recipients, 80 early-disseminated cancer cells sufficed to induce lethal carcinosis. Therefore, release from dormancy of early-disseminated cancer cells may frequently account for metachronous metastasis.

The hematopoietic system-specific minor histocompatibility antigen HA-1 shows aberrant expression in epithelial cancer cells.

Allogeneic stem cell transplantation (SCT) can induce curative graft-versus-tumor reactions in patients with hematological malignancies and solid tumors. The graft-versus-tumor reaction after human histocompatibility leukocyte antigen (HLA)-identical SCT is mediated by alloimmune donor T cells specific for polymorphic minor histocompatibility antigens (mHags). Among these, the mHag HA-1 was found to be restricted to the hematopoietic system. Here, we report on the HA-1 ribonucleic acid expression by microdissected carcinoma tissues and by single disseminated tumor cells isolated from patients with various epithelial tumors. The HA-1 peptide is molecularly defined, as it forms an immunogenic peptide ligand with HLA-A2 on the cell membrane of carcinoma cell lines. HA-1-specific cytotoxic T cells lyse epithelial tumor cell lines in vitro, whereas normal epithelial cells are not recognized. Thus, HA-1-specific immunotherapy combined with HLA-identical allogeneic SCT may now be feasible for patients with HA-1(+) carcinomas.

Cutaneous T-cell lymphoma-associated lung cancers show chromosomal aberrations differing from primary lung cancer.

Cutaneous T-cell lymphoma (CTCL) patients have an increased risk of certain secondary cancers, the most common of which are lung cancers, especially small cell lung cancer. To reveal the molecular pathogenesis underlying CTCL-associated lung cancer, we analyzed genomic aberrations in CTCL-associated and reference lung cancer samples. DNA derived from microdissected lung cancer cells of five CTCL-associated lung cancers and five reference lung cancers without CTCL association was analyzed by comparative genomic hybridization (CGH). Fluorescent in situ hybridization (FISH), immunohistochemistry (IHC), and loss of heterozygosity (LOH) analysis were performed for selected genes. In CTCL-associated lung cancer, CGH revealed chromosomal aberrations characterizing both lung cancer and CTCL, but also losses of 1p, and 19, and gains of 4q and 7, hallmarks of CTCL. LOH for the CTCL-associated NAV3 gene was detected in two of the four informative primary lung cancers. FISH revealed increased copy number of the KIT gene in 3/4 of CTCL-associated lung cancers and 1/5 of primary lung cancers. PDGFRA and VEGFR2 copy numbers were also increased. IHC showed moderate KIT expression when the gene copy number was increased. CTCL-associated lung cancer shows chromosomal aberrations different from primary lung cancer, especially amplifications of 4q, a chromosome arm frequently deleted in the latter tumor type. Copy numbers and expression of selected genes in chromosome 4 differed between CTCL-associated and reference lung cancers. These preliminary observations warrant further prospective studies to identify the common underlying factors between CTCL and CTCL-associated lung cancer.

Clinicopathological characterization and genomic aberrations in subcutaneous panniculitis-like T-cell lymphoma.

Subcutaneous panniculitis-like T-cell lymphomas (SPTLs) represent a rare, difficult-to-diagnose, and poorly characterized subtype of cutaneous T-cell lymphomas (CTCLs) affecting younger people more than the other CTCL forms. We performed a thorough clinical, immunohistological, and molecular analysis of nine Finnish SPTL patients. Specifically, we performed single-cell comparative genomic hybridization (CGH) from laser microdissected, morphologically malignant SPTL cells, as well as loss of heterozygosity (LOH) and fluorescence in situ hybridization (FISH) analysis for the NAV3 (neuron navigator 3) gene. CGH revealed large numbers of DNA copy number changes, the most common of which were losses of chromosomes 1pter, 2pter, 10qter, 11qter, 12qter, 16, 19, 20, and 22 and gains of chromosomes 2q and 4q. Some of the DNA copy number aberrations in SPTL, such as loss of 10q, 17p, and chromosome 19, overlap with those characteristic of common forms of CTCL (mycosis fungoides (MF) and Sezary syndrome (SS)), whereas 5q and 13q gains characterize SPTL. Allelic NAV3 aberrations (LOH or deletion by FISH), previously found in MF and SS, were identified in 44% of the SPTL samples. This study demonstrates that SPTL is also moleculocytogenetically a uniform entity of CTCL and supports the current World Health Organization-European Organization for Research and Treatment of Cancer (WHO-EORTC) classification defining SPTL as a subgroup of its own.

Specific ablation of the nidogen-binding site in the laminin gamma1 chain interferes with kidney and lung development.

Basement membrane assembly is of crucial importance in the development and function of tissues and during embryogenesis. Nidogen 1 was thought to be central in the assembly processes, connecting the networks formed by collagen type IV and laminins, however, targeted inactivation of nidogen 1 resulted in no obvious phenotype. We have now selectively deleted the sequence coding for the 56 amino acid nidogen-binding site, gamma1III4, within the Lamc1 gene by gene targeting. Here, we show that mice homozygous for the deletion die immediately after birth, showing renal agenesis and impaired lung development. These developmental defects were attributed to locally restricted ruptures in the basement membrane of the elongating Wolffian duct and of alveolar sacculi. These data demonstrate that an interaction between two basement membrane proteins is required for early kidney morphogenesis in vivo.