Because of the paucity of available tissue, little information has previously been available regarding the gene expression profiles of primary melanomas. To understand the molecular basis of melanoma progression, we compared the gene expression profiles of a series of nevi, primary melanomas, and melanoma metastases. We found that metastatic melanomas exhibit two dichotomous patterns of gene expression, which unexpectedly reflect gene expression differences already apparent in comparing laser-capture microdissected radial and vertical phases of a large primary melanoma. Unsupervised hierarchical clustering accurately separated nevi and primary melanomas. Multiclass significance analysis of microarrays comparing normal skin, nevi, primary melanomas, and the two types of metastatic melanoma identified 2,602 transcripts that significantly correlated with sample class. These results suggest that melanoma pathogenesis can be understood as a series of distinct molecular events. The gene expression signatures identified here provide the basis for developing new diagnostics and targeting therapies for patients with malignant melanoma.bioinformatics ͉ human ͉ microarray ͉ metastasis ͉ laser capture I n the current staging system for cutaneous melanoma, vertical thickness of the primary tumor is the dominant prognostic factor, belying the fact that a subset of thin tumors metastasize, whereas some thick tumors do not undergo metastasis (1). The original melanoma tumor progression model is characterized by an initial radial growth phase, encompassing in situ and minimally invasive tumors (2). This phase is followed by the development of vertical growth phase, which has been postulated to be the first point at which the tumor gains metastatic capacity. However, metastasis occurs, although with decreased frequency, in patients whose primary melanoma pathology exhibits only a radial growth pattern (3). Previous transcriptome analysis in melanoma defined a cluster of genes expressed in a majority of metastatic melanomas (4); however, this cluster was not related to radial or vertical growth, and precursor nevi (moles) and primary melanomas were not examined. Likewise, mutations in B-RAF occur commonly in both nevi (5) and melanoma (6), and, thus, do not distinguish progressive stages in melanoma progression. In this study, we used cDNA expression array profiling to characterize the global patterns of transcript modulation that underlie the various phases in the known tumor progression pathway of melanoma. MethodsStudy Subjects. Samples from melanoma patients and nevus volunteers presenting to the Melanoma Center were obtained with informed consent under a protocol approved by the UCSF Institutional Review Board. After biopsy, all samples were frozen in OCT freezing medium over dry ice. Subsequently, samples were processed for hematoxylin͞eosin staining and confirmed by pathologic review. Only samples comprised of Ͼ95% tumor cells were analyzed.

These data suggest that sub-renal capsule and orthotopic grafting of human prostate tissue can be used for many basic scientific and translational studies.

Microcalcifications (MCs) are routinely used to detect breast cancer in mammography. Little is known, however, about their materials properties and associated organic matrix, or their correlation to breast cancer prognosis. We combine histopathology, Raman microscopy, and electron microscopy to image MCs within snap-frozen human breast tissue and generate micron-scale resolution correlative maps of crystalline phase, trace metals, particle morphology, and organic matrix chemical signatures within high grade ductal carcinoma in situ (DCIS) and invasive cancer. We reveal the heterogeneity of mineral-matrix pairings, including punctate apatitic particles (<2 µm) with associated trace elements (e.g., F, Na, and unexpectedly Al) distributed within the necrotic cores of DCIS, and both apatite and spheroidal whitlockite particles in invasive cancer within a matrix containing spectroscopic signatures of collagen, non-collagen proteins, cholesterol, carotenoids, and DNA. Among the three DCIS samples, we identify key similarities in MC morphology and distribution, supporting a dystrophic mineralization pathway. This multimodal methodology lays the groundwork for establishing MC heterogeneity in the context of breast cancer biology, and could dramatically improve current prognostic models.

Scant published data exist on redesigning pathology practice based on error data. In this first step of an Agency for Healthcare Research and Quality patient safety project, we measured the performance metrics of thyroid gland fine-needle aspiration, performed root cause analysis to determine the causes of error, and proposed error-reduction initiatives to address specific errors. Eleven cytologists signed out 1,543 thyroid gland aspirates in 2 years, and surgical pathology follow-up was obtained in 364 patients. Of the 364 patients, 91 (25.0%) had a false-negative diagnosis and 36 (9.9%) a false-positive diagnosis. Root cause analysis showed that major sources of error were pre-analytic (poor specimen quality) and analytic (interpretation of unsatisfactory specimens as nonneoplastic and lack of diagnostic category standardization). We currently are evaluating the effectiveness of error reduction initiatives that target pre-analytic and analytic portions of the diagnostic pathway.