Formalin‐fixed, paraffin‐embedded (FFPE) sections of breast tissue are used by pathologists to correctly type and grade the primary tumor and to assess the extent of a patient’s disease. The cut sections represent a reproducible likeness of the morphology of the tissue when viewed through a microscope, although the fixation technique creates some artifacts. What is not known is how the sections differ chemically from how the tumor would look or behave within the breast. Raman spectroscopy is, like many other optical techniques, fast, noninvasive, and generally inexpensive. The advantage Raman has over other techniques is its powerful ability to identify specific chemicals, molecules, and bonds within a sample. Using Raman spectroscopy the chemicals present in both fresh tissue and FFPE sections can be identified and compared, allowing any differences between them to be identified. This information may be useful to the pathologist as an aid to further treatment regimes or novel molecular techniques, and as an aid to patient management. If these sections are found to be chemically similar to fresh tissue, they could be used to further characterize breast tumors, particularly rare tumors, using Raman spectroscopy.

BACKGROUND:Given the large number of genes purported to be prognostic for breast cancer, it would be optimal if the genes identified are not confounded by the continuously changing systemic therapies. The aim of this study was to discover and validate a breast cancer prognostic expression signature for distant metastasis in untreated, early stage, lymph node-negative (N-) estrogen receptor-positive (ER+) patients with extensive follow-up times.METHODS:197 genes previously associated with metastasis and ER status were profiled from 142 untreated breast cancer subjects. A "metastasis score" (MS) representing fourteen differentially expressed genes was developed and evaluated for its association with distant-metastasis-free survival (DMFS). Categorical risk classification was established from the continuous MS and further evaluated on an independent set of 279 untreated subjects. A third set of 45 subjects was tested to determine the prognostic performance of the MS in tamoxifen-treated women.RESULTS:A 14-gene signature was found to be significantly associated (p < 0.05) with distant metastasis in a training set and subsequently in an independent validation set. In the validation set, the hazard ratios (HR) of the high risk compared to low risk groups were 4.02 (95% CI 1.91-8.44) for the endpoint of DMFS and 1.97 (95% CI 1.28 to 3.04) for overall survival after adjustment for age, tumor size and grade. The low and high MS risk groups had 10-year estimates (95% CI) of 96% (90-99%) and 72% (64-78%) respectively, for DMFS and 91% (84-95%) and 68% (61-75%), respectively for overall survival. Performance characteristics of the signature in the two sets were similar. Ki-67 labeling index (LI) was predictive for recurrent disease in the training set, but lost significance after adjustment for the expression signature. In a study of tamoxifen-treated patients, the HR for DMFS in high compared to low risk groups was 3.61 (95% CI 0.86-15.14).CONCLUSION:The 14-gene signature is significantly associated with risk of distant metastasis. The signature has a predominance of proliferation genes which have prognostic significance above that of Ki-67 LI and may aid in prioritizing future mechanistic studies and therapeutic interventions.

Studying cellular protein-protein interactions in situ requires a technique such as fluorescence resonance energy transfer (FRET) which is sensitive on the nanometer scale. Observing FRET is significantly simplified if the fluorescence lifetime of the donor can be monitored. Results from live cells and tissue micro arrays are presented from an automated microscope incorporating time-domain TCSPC fluorescence lifetime imaging (FLIM). Novel hardware and software with a modular approach and scripting abilities allow us to work towards speed-optimized acquisition and ease of use to bring FLIM into the high-throughput regime.

Tissue microarrays have been used effectively to study representative tissue from large groups of patients, with minimal technical and reagent costs. The construction of these arrays may appear complex, but with the use of a semiautomated tissue arrayer and a degree of manual dexterity, symmetrical, high-density arrays can be produced. Here, we highlight where problems in the construction, cutting, and evaluation of tissue microarrays can occur and how these can be prevented.