Breast cancer patients with the same stage of disease can have markedly different treatment responses and overall outcome. The strongest predictors for metastases (for example, lymph node status and histological grade) fail to classify accurately breast tumours according to their clinical behaviour. Chemotherapy or hormonal therapy reduces the risk of distant metastases by approximately one-third; however, 70-80% of patients receiving this treatment would have survived without it. None of the signatures of breast cancer gene expression reported to date allow for patient-tailored therapy strategies. Here we used DNA microarray analysis on primary breast tumours of 117 young patients, and applied supervised classification to identify a gene expression signature strongly predictive of a short interval to distant metastases ('poor prognosis' signature) in patients without tumour cells in local lymph nodes at diagnosis (lymph node negative). In addition, we established a signature that identifies tumours of BRCA1 carriers. The poor prognosis signature consists of genes regulating cell cycle, invasion, metastasis and angiogenesis. This gene expression profile will outperform all currently used clinical parameters in predicting disease outcome. Our findings provide a strategy to select patients who would benefit from adjuvant therapy.

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Gene expression profiling predicts clinical outcome of breast cancer

Patterns of DNA methylation and chromatin structure are profoundly altered in neoplasia and include genome-wide losses of, and regional gains in, DNA methylation. The recent explosion in our knowledge of how chromatin organization modulates gene transcription has further highlighted the importance of epigenetic mechanisms in the initiation and progression of human cancer. These epigenetic changes -- in particular, aberrant promoter hypermethylation that is associated with inappropriate gene silencing -- affect virtually every step in tumour progression. In this review, we discuss these epigenetic events and the molecular alterations that might cause them and/or underlie altered gene expression in cancer.

The fundamental role of epigenetic events in cancer

Tumours are known as wounds that do not heal - this implies that cells that are involved in angiogenesis and the response to injury, such as endothelial cells and fibroblasts, have a prominent role in the progression, growth and spread of cancers. Fibroblasts are associated with cancer cells at all stages of cancer progression, and their structural and functional contributions to this process are beginning to emerge. Their production of growth factors, chemokines and extracellular matrix facilitates the angiogenic recruitment of endothelial cells and pericytes. Fibroblasts are therefore a key determinant in the malignant progression of cancer and represent an important target for cancer therapies.

Fibroblasts in cancer

Stromal Fibroblasts Present in Invasive Human Breast Carcinomas Promote Tumor Growth and Angiogenesis through Elevated SDF-1/CXCL12 Secretion

Life is the interplay between structure and energy, yet the role of energy deficiency in human disease has been poorly explored by modern medicine. Since the mitochondria use oxidative phosphorylation (OXPHOS) to convert dietary calories into usable energy, generating reactive oxygen species (ROS) as a toxic by-product, I hypothesize that mitochondrial dysfunction plays a central role in a wide range of age-related disorders and various forms of cancer. Because mitochondrial DNA (mtDNA) is present in thousands of copies per cell and encodes essential genes for energy production, I propose that the delayed-onset and progressive course of the agerelated diseases results from the accumulation of somatic mutations in the mtDNAs of post-mitotic tissues. The tissue-specific manifestations of these diseases may result from the varying energetic roles and needs of the different tissues. The variation in the individual and regional predisposition to degenerative diseases and cancer may result from the interaction of modern dietary caloric intake and ancient mitochondrial genetic polymorphisms. Therefore the mitochondria provide a direct link between our environment and our genes and the mtDNA variants that permitted our forbears to energetically adapt to their ancestral homes are influencing our health today.

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A Mitochondrial Paradigm of Metabolic and Degenerative Diseases, Aging, and Cancer: A Dawn for Evolutionary Medicine

Endometrial "hyperplasia," as currently diagnosed, includes the changes caused by an abnormal hormonal state and those caused by a separate category of monoclonal premalignant disease. The appearance of the disease in these 2 functional categories is discontinuous, permitting more specific diagnosis of the condition using the terms "benign endometrial hyperplasia" and "endometrial intraepithelial neoplasia" (EIN), respectively. Benign endometrial hyperplasia involves the entire endometrial compartment and, with protracted estrogen exposure, shows the progressive development of cysts, remodeled glands, vascular thrombi, and stromal microinfarcts. They are best construed as a sequence of changes whereby the appearance at any single time point is uniquely dependent on the preceding combination and the duration of hormonal exposures. In contrast, the premalignant clone of an EIN lesion is characteristically offset from the background endometrium by its altered cytology and crowded architecture. The use of an internal standard for cytology assessment, combined with the distinctive topography of a clonal process, enables the diagnosis of EIN lesions with a long-term cancer risk 45-fold greater than that of their benign endometrial hyperplasia counterparts. The resolution of hormonal and premalignant subsets of traditional "endometrial hyperplasias" is possible using redefined diagnostic criteria, enabling patient therapy to be appropriately matched with the underlying disease mechanisms.

Benign endometrial hyperplasia sequence and endometrial intraepithelial neoplasia.

The protooncogene c-mos is expressed in murine reproductive tissues, producing transcripts of 17 and 14 kilobases in testis and ovary, respectively In situ hybridization analysis of c-mos expression in histological sections of mouse ovaries revealed that oocytes are the predominant if not exclusive source of c-mos transcripts c-mos transcripts accumulate in growing oocytes, increasing 40- to 90-fold during oocyte and follicular development c-mos transcripts were also detected in male germ cells and are most abundant after the cells have entered the haploid stage of spermatogenesis This developmentally regulated pattern of c-mos expression in oocytes and spermatogenic cells suggests that the c-mos gene product may have a function in normal germ-cell differentiation or early embryogenesis

George L. Mutter

Papers

Benign endometrial hyperplasia sequence and endometrial intraepithelial neoplasia.

Distinct developmental patterns of c-mos protooncogene expression in female and male mouse germ cells.

Prediction of endometrial carcinoma by subjective endometrial intraepithelial neoplasia diagnosis

High-grade fimbrial-ovarian carcinomas are unified by altered p53, PTEN and PAX2 expression

Expression of DAZ, an azoospermia factor candidate, in human spermatogonia.