Multiple different oncogenes have been described previously to be amplified in breast cancer including HER2, EGFR, MYC, CCND1, and MDM2. Gene amplification results in oncogene overexpression but may also serve as an indicator of genomic instability. As such, presence of one or several gene amplifications may have prognostic significance. To assess the prognostic importance of amplifications and coamplifications of HER2, EGFR, MYC, CCND1, and MDM2 in breast cancer, we analyzed a breast cancer tissue microarray containing samples from 2197 cancers with follow-up information. Fluorescence in situ hybridizations revealed amplifications of CCND1 in 20.1%, HER2 in 17.3%, MDM2 in 5.7%, MYC in 5.3%, and EGFR in 0.8% of the tumors. All gene amplifications were significantly associated with high grade. HER2 (P < 0.001) and MYC amplification (P < 0.001) were also linked to shortened survival. In case of HER2, this was independent of grade, pT, and pN categories. MYC amplification was almost 3 times more frequent in medullary cancer (15.9%), than in the histologic subtype with the second highest frequency (ductal; 5.6%; P ‫؍‬ 0.0046). HER2 and MYC amplification were associated with estrogen receptor/progesterone receptor negativity (P < 0.001) whereas CCND1 amplification was linked to estrogen receptor/progesterone receptor positivity (P < 0.001). Coamplifications were more prevalent than expected based on the individual frequencies. Coamplifications of one or several other oncogenes occurred in 29.6% of CCND1, 43% of HER2, 55.7% of MDM2, 65% of MYC, and 72.8% of EGFR-amplified cancers. HER2/MYC-coamplified cancers had a worse prognosis than tumors with only one of these amplifications. Furthermore, a gradual decrease of survival was observed with increasing number of amplifications. In conclusion, these data support a major prognostic impact of genomic instability as determined by a broad gene amplification survey in breast cancer.

This contribution is part of the special series of Inaugural Articles by members of the National Academy of Sciences elected in 2009.Contributed by V. Craig Jordan, September 14, 2011 (sent for review June 21, 2011) In laboratory studies, acquired resistance to long-term antihormonal therapy in breast cancer evolves through two phases over 5 y. Phase I develops within 1 y, and tumor growth occurs with either 17β-estradiol (E 2 ) or tamoxifen. Phase II resistance develops after 5 y of therapy, and tamoxifen still stimulates growth; however, E 2 paradoxically induces apoptosis. This finding is the basis for the clinical use of estrogen to treat advanced antihormone-resistant breast cancer. We interrogated E 2 -induced apoptosis by analysis of gene expression across time (2-96 h) in MCF-7 cell variants that were estrogen-dependent (WS8) or resistant to estrogen deprivation and refractory (2A) or sensitive (5C) to E 2 -induced apoptosis. We developed a method termed differential area under the curve analysis that identified genes uniquely regulated by E 2 in 5C cells compared with both WS8 and 2A cells and hence, were associated with E 2 -induced apoptosis. Estrogen signaling, endoplasmic reticulum stress (ERS), and inflammatory response genes were overrepresented among the 5C-specific genes. The identified ERS genes indicated that E 2 inhibited protein folding, translation, and fatty acid synthesis. Meanwhile, the ERS-associated apoptotic genes Bcl-2 interacting mediator of cell death (BIM; BCL2L11) and caspase-4 (CASP4), among others, were induced. Evaluation of a caspase peptide inhibitor panel showed that the CASP4 inhibitor z-LEVD-fmk was the most active at blocking E 2 -induced apoptosis. Furthermore, z-LEVD-fmk completely prevented poly (ADP-ribose) polymerase (PARP) cleavage, E 2 -inhibited growth, and apoptotic morphology. The up-regulated proinflammatory genes included IL, IFN, and arachidonic acid-related genes. Functional testing showed that arachidonic acid and E 2 interacted to superadditively induce apoptosis. Therefore, these data indicate that E 2 induced apoptosis through ERS and inflammatory responses in advanced antihormone-resistant breast cancer.aromatase inhibitor | antihormonal resistance | estrogen receptor | gene expression microarrays | selective estrogen receptor modulator E lucidation of the basic structure function relationships of synthetic estrogens based on either stilbene (1) or triphenylethylene (2) was a landmark achievement that continues to have major therapeutic implications to this day. The first successful chemical therapy for the treatment of any cancer was the use of high-dose synthetic estrogen for the treatment of metastatic breast cancer (3). Response rates for patients who were more than a decade beyond menopause were about 30%. Importantly, treatment near menopause was ineffective, and therefore, tumor responsiveness was related to the duration of estrogen deprivation. In 1970, Alexander Haddow commented that "the extraordinary extent of tumor regression observed in...

Adjuvant chemotherapy decisions in breast cancer are increasingly based on the pathologist's assessment of tumor proliferation. The Swiss Working Group of Gyneco- and Breast Pathologists has surveyed inter- and intraobserver consistency of Ki-67-based proliferative fraction in breast carcinomas.MethodsFive pathologists evaluated MIB-1-labeling index (LI) in ten breast carcinomas (G1, G2, G3) by counting and eyeballing. In the same way, 15 pathologists all over Switzerland then assessed MIB-1-LI on three G2 carcinomas, in self-selected or pre-defined areas of the tumors, comparing centrally immunostained slides with slides immunostained in the different laboratoires. To study intra-observer variability, the same tumors were re-examined 4 months later.ResultsThe Kappa values for the first series of ten carcinomas of various degrees of differentiation showed good to very good agreement for MIB-1-LI (Kappa 0.56–0.72). However, we found very high inter-observer variabilities (Kappa 0.04–0.14) in the read-outs of the G2 carcinomas. It was not possible to explain the inconsistencies exclusively by any of the following factors: (i) pathologists' divergent definitions of what counts as a positive nucleus (ii) the mode of assessment (counting vs. eyeballing), (iii) immunostaining technique, and (iv) the selection of the tumor area in which to count. Despite intensive confrontation of all participating pathologists with the problem, inter-observer agreement did not improve when the same slides were re-examined 4 months later (Kappa 0.01–0.04) and intra-observer agreement was likewise poor (Kappa 0.00–0.35).ConclusionAssessment of mid-range Ki-67-LI suffers from high inter- and intra-observer variability. Oncologists should be aware of this caveat when using Ki-67-LI as a basis for treatment decisions in moderately differentiated breast carcinomas.

Mitotic figure (MF) counting is important in the evaluation of many tumor types. Inadequate fixation, crush artefacts, the presence of many apoptoses, or the rarity of MFs in a given lesion can make the determination of the mitotic index a very time-consuming or even impossible task, especially for novices. We evaluated the potential of the two commercially available mitotic markers MPM-2 and Phospho-Histone H3 Ser28 (PHH3) for improving mitotic counting. Formalin-fixed tissue of 1 lymphoma, 19 epithelial, 25 mesenchymal, and 10 melanocytic tumors was immunohistochemically stained with both antibodies. Mitotic counts of each tumor sample were determined by a pathologist and three residents in the hematoxylin and eosin and in both immunohistochemical stainings. Because of the higher sensitivity of the immunohistochemical stainings for MFs, average mitotic counts per 10 HPF were higher with MPM-2 (11.0) and PHH3 (10.1) than with hematoxylin and eosin (5.9) staining. The precise distinction of MFs from apoptoses and the visualization of the distribution of MFs uncovering mitotic hotspots, even at low magnification, turned out to be major advantages of both mitotic markers. In addition, the average time needed to establish the mitotic count was reduced by 40.3% with MPM-2 and by 50.4% with PHH3. MPM-2 and PHH3 were subjectively rated by all pathologists involved in this study to be very helpful in mitotic counting, especially in melanocytic and mesenchymal lesions but less so in epithelial tumors. Both markers have hence been successfully introduced in our laboratory for the routine assessment of MFs in melanocytic and mesenchymal tumors.

Epidermal growth factor receptor (EGFR) gene mutations and increased copy numbers are considered as predictors of response to EGFR tyrosine kinase inhibitors (EGFR-TKI) in non-small-cell lung cancer (NSCLC). Lung cancer diagnosis is often based on cytology alone. However, almost all published data on EGFR gene analyses were obtained from biopsies. This study tested the feasibility of EGFR gene analyses on cytological specimens. Eighty-four cytological specimens from NSCLCs were prospectively analysed for EGFR gene mutation in exons 18 -21 and EGFR gene copy numbers were evaluated by fluorescence in situ hybridisation (FISH). A FISHpositive result was defined according to the criteria by Cappuzzo et al established for biopsies of NSCLCs. Fluorescence in situ hybridisation results of cytological specimens were compared to the FISH results on matching biopsies (n ¼ 33). Initial diagnosis of NSCLC was solely based on cytology in 37 out of 84 (44.0%) patients. Out of 80 NSCLCs, 6 (7.5%) showed EGFR gene mutations. Out of 67 cancers, 45 (67.2%) were FISH positive on cytological specimens. Comparison of FISH showed a FISH-positive result in 21 out of 33 (63.6%) cytological specimens but in only 8 out of 33 (24.2%) matched biopsies. Epidermal growth factor receptor gene analyses are well applicable to cytological specimens. The high FISH-positive rate of NSCLC on cytological specimens contrasts with the low rate on biopsies when previously suggested criteria are used. New criteria for a positive EGFR FISH status to predict response to therapy with EGFR-TKI need to be defined for cytological specimens.