Influence of whole arm loss of chromosome 16q on gene expression patterns in oestrogen receptor-positive, invasive breast cancer.

A whole chromosome arm loss of 16q belongs to the most frequent and earliest chromosomal alterations in invasive and in situ breast cancers of all common subtypes. Besides E-cadherin, several putative tumour suppressor genes residing on 16q in breast cancer have been investigated. However, the significance of these findings has remained unclear. Thus, other mechanisms leading to gene loss of function (eg haploinsufficiency, or distortion of multiple regulative subnetworks) remain to be tested as a hypothesis. To define the effect on gene expression of whole-arm loss of chromosome 16q in invasive breast cancer, we performed global gene expression analysis on a series of 18 genetically extensively characterized invasive ductal breast carcinomas and verified the results by quantitative real-time PCR (qRT-PCR). The distribution of the differential genes across the genome and their expression status was studied. A second approach by qRT-PCR in an independent series of 30 breast carcinomas helped to narrow down the observed effect. Whole-arm chromosome 16q losses, irrespective of other chromosomal changes, are associated with decreased expression of a number of candidate genes located on 16q (eg CDA08, CGI-128, SNTB2, NQO1, SF3B3, KIAA0174, ATBF1, GABARAPL2, KARS, GCSH, MBTPS1 and ZDHHC7) in breast carcinomas with a low degree of genetic instability. qRT-PCR provided evidence to suggest that the expression of these genes was reduced in a gene dosage-dependent manner. The differential expression of the candidate genes according to the chromosomal 16q-status vanished in genetically advanced breast cancer cases and changed ER status. These results corroborate previous reports about the importance of whole-arm loss of chromosome 16q in breast carcinogenesis and give evidence for the first time that haploinsufficiency, in the sense of a gene dosage effect, might be an important contributing factor in the early steps of breast carcinogenesis.

Calcifications in digital mammographic screening: improvement of early detection of invasive breast cancers?

PURPOSE: To evaluate the relevance of calcifications for invasive breast cancer detection in population-based digital mammographic screening. MATERIALS AND METHODS: This study was approved by an independent ethics committee, and no additional informed consent was required. Prospectively documented radiologic cancer features were correlated with pathologic characteristics in 241 breast malignancies diagnosed in 24067 participating women aged 50-69 years (part of the digital German Screening Program; initial screening rate, 92%; detection rate [DR], 1.0%; recall rate [RR], 7.5%). The rates of invasive cancers detected on the basis of calcifications were analyzed against pathologic tumor categories (pT categories) and histologic grades. For comparison of the study data with results of analog screening, data from the literature regarding calcification-specific RR, DR, and positive predictive value for recall (PPV(1)) were calculated. RESULTS: The calcification-specific RR was 1.7% (416 of 24067). The calcification-specific DR for invasive cancer was 0.12% (29 of 24067), and the PPV(1) was 7.0% (29 of 416). Of all malignancies detected on the basis of calcification, 38% (29 of 77) were invasive. pT1 cancers showed an inverse association between tumor size and rate of detection on the basis of calcification; differences in rates among pT1 subcategories were statistically significant (P < .001). The proportion of grade 1 pT1 cancers detected on the basis of calcification (eight of 27) did not differ significantly from that of cancers detected on the basis of other radiologic features (46 of 108, P = .24). The calcification-specific invasive cancer DR was significantly higher for digital than for analog mammography. CONCLUSION: One-third of malignancies detected on the basis of calcifications only are invasive cancers. They tend to be smaller but not less aggressive than invasive cancers detected on the basis of other features. Compared with published results of analog screening, digital screening offers the potential to increase the rate of invasive cancers detected on the basis of calcifications in population-based mammographic screening.

Tiling path genomic profiling of grade 3 invasive ductal breast cancers.

PURPOSE: To characterize the molecular genetic profiles of grade 3 invasive ductal carcinomas of no special type using high-resolution microarray-based comparative genomic hybridization (aCGH) and to identify recurrent amplicons harboring putative therapeutic targets associated with luminal, HER-2, and basal-like tumor phenotypes. EXPERIMENTAL DESIGN: Ninety-five grade 3 invasive ductal carcinomas of no special type were classified into luminal, HER-2, and basal-like subgroups using a previously validated immunohistochemical panel. Tumor samples were microdissected and subjected to aCGH using a tiling path 32K BAC array platform. Selected regions of recurrent amplification were validated by means of in situ hybridization. Expression of genes pertaining to selected amplicons was investigated using quantitative real-time PCR and gene silencing was done using previously validated short hairpin RNA constructs. RESULTS: We show that basal-like and HER-2 tumors are characterized by "sawtooth" and "firestorm" genetic patterns, respectively, whereas luminal cancers were more heterogeneous. Apart from confirming known amplifications associated with basal-like (1q21, 10p, and 12p), luminal (8p12, 11q13, and 11q14), and HER-2 (17q12) cancers, we identified previously unreported recurrent amplifications associated with each molecular subgroup: 19q12 in basal-like, 1q32.1 in luminal, and 14q12 in HER-2 cancers. PPM1D gene amplification (17q23.2) was found in 20% and 8% of HER-2 and luminal cancers, respectively. Silencing of PPM1D by short hairpin RNA resulted in selective loss of viability in tumor cell lines harboring the 17q23.2 amplification. CONCLUSIONS: Our results show the power of aCGH analysis in unraveling the genetic profiles of specific subgroups of cancer and for the identification of novel therapeutic targets.

Loss of 16q in high grade breast cancer is associated with estrogen receptor status: Evidence for progression in tumors with a luminal phenotype?

Loss of the long arm of chromosome 16 (16q) is observed in the vast majority of low grade/grade I (GI) invasive ductal carcinomas of no special type (IDC-NSTs), whereas this event is uncommonly seen in high grade/grade III (GIII) IDC-NSTs. Together with data on the pathology and genetics of breast cancer recurrences, this has led to the proposal that GI and GIII breast cancers evolve through distinct genetic pathways and that progression from GI to GIII is an unlikely biological phenomenon. We compared the genomic profiles of GIII-IDC-NSTs with 16q whole arm loss (16qWL) according to estrogen receptor (ER) status. 16qWL was found in 36.5% of cases and was significantly associated with ER expression and luminal phenotype. ER+ GIII-IDC-NSTs with 16qWL displayed significantly higher levels of genomic instability than ER+ IDC-NSTs without 16qWL. Furthermore, ER+ and ER- IDC-NSTs stratified according to the presence of 16qWL harbored distinct patterns of genetic aberrations. Interestingly, ER+/16qWL tumors displayed genetic features usually found in tumors with homologous DNA repair defects and significantly more frequently harbored heterozygous loss of BRCA2 than the remaining ER+ cancers. Our results demonstrate that approximately one third of GIII tumors harbor 16qWL, confirming that progression from low to high grade breast cancer is not found in the majority of breast cancers. 16qWL was significantly more prevalent in ER+/luminal GIII-IDC-NSTs. Given that GI breast cancers harbor a luminal phenotype, our results suggest that if progression from GI to GIII breast cancer does happen, it may preferentially occur in breast cancers of luminal phenotype.

[Salivary duct carcinomas comprise phenotypically and genotypically diverse high grade neoplasms]. / Speichelgangkarzinome--ein Spektrum phänotypisch und genotypisch heterogener Tumoren.

Salivary duct carcinomas (SDC) are high grade neoplasms morphologically reminiscent of breast ductal carcinomas. Whereas the latter are well characterized, the body of immunophenotypic and cytogenetic data on SDC is limited. We studied 23 SDC by conventional histology, immunohistology, in situ hybridization, and comparative genomic hybridization (CGH). Data were subjected to biomathematical analysis in comparison to previously characterized breast ductal carcinomas in situ and invasive ductal carcinoma cases. Most SDC stained for cytokeratins (Ck) Ck 8/18 (77 %) or Ck 5/6 (30 %), 30 % of cases expressed the androgen receptor (AR), 14 cases (63 %) expressed c-erbB2, and one case stained for prostate specific antigen. Except for two cases, Ck 8/18 and Ck 5/6 were not coexpressed. Ck 8/18 expression positively correlated with presence of c-erbB2 and AR. At variance, Ck 5/6 correlated positively with p63 and inversely with both AR and c-erbB2 expression. Ck 5/6 and p 63 co-expression was also found in a distinct population of ductal epithelial cells of normal salivary glands. CGH analysis of SDC revealed increasing numbers of alterations in correlation with advanced diseases, but no recurrent alterations. Cluster analysis of phenotypic and genotypic markers assigned both salivary and breast carcinomas to numerous clusters independent of the primary tumour site. Although undistinguishable by conventional histology, SDC are heterogeneous, comprising at least two immunophenotypically distinct subgroups of neoplasms. Cluster analysis suggests several distinct patterns of gene expression common to both primary sites explaining morphologic parallels between SDC and high grade breast cancer.

Adenomyoepithelial tumours and myoepithelial carcinomas of the breast--a spectrum of monophasic and biphasic tumours dominated by immature myoepithelial cells.

BACKGROUND: Adenomyoepithelial tumours and myoepithelial carcinomas of the breast are primarily defined by the presence of neoplastic cells with a myoepithelial immunophenotype. Current classification schemes are based on purely descriptive features and an assessment of individual prognosis is still problematic. METHODS: A series of 27 adenomyoepithelial tumours of the breast was analysed immunohistochemically with antibodies directed against various cytokeratins, p63, smooth muscle alpha-actin (SMA) and vimentin. Additionally, double immunofluorescence and comparative genomic hybridisation (CGH) was performed. RESULTS: Immunohistochemically, all the tumours showed a constant expression of high molecular weight cytokeratins (Ck) Ck5 and Ck14, p63, SMA and vimentin. With exception of one case diagnosed as myoepithelial carcinoma, all tested tumours expressed low molecular weight cytokeratin Ck18 in variable proportions of cells. Even in monophasic tumours lacking obvious glandular differentiation in conventional staining, a number of neoplastic cells still expressed those cytokeratins. Double immunofluorescence revealed tumour cells exclusively staining for Ck5/Ck14 in the presence of other cell populations that co-expressed high molecular weight Ck5/Ck14 as well as either low molecular weight Ck8/18 or SMA. Based on morphology, we assigned the series to three categories, benign, borderline and malignant. This classification was supported by a stepwise increase in cytogenetic alterations on CGH. CONCLUSION: Adenomyoepithelial tumours comprise a spectrum of neoplasms consisting of an admixture of glandular and myoepithelial differentiation patterns. As a key component SMA-positive cells co-expressing cytokeratins could be identified. Although categorisation of adenomyoepithelial tumours in benign, borderline and malignant was supported by results of CGH, any assessment of prognosis requires to be firmly based on morphological grounds. At present it is not yet clear, if and to what extent proposed Ck5-positive progenitor cells contribute to the immunohistochemical and morphological heterogeneity of these neoplasms of the breast.

The origin of vimentin expression in invasive breast cancer: epithelial-mesenchymal transition, myoepithelial histogenesis or histogenesis from progenitor cells with bilinear differentiation potential?

Vimentin expression is a rather rare finding in invasive breast cancer, and is associated with high tumour invasiveness and chemoresistance. It is currently explained by two different biological theories: direct histogenetic derivation from myoepithelial cells, and epithelial-mesenchymal transition (EMT) reflecting the end-stage of breast cancer dedifferentiation. In this study we aimed to obtain further insights into the biological hallmarks of these vimentin-expressing breast cancers. We applied immunohistochemistry for vimentin and 15 other differentiation markers to a series of 364 invasive breast cancer cases, using tissue microarray technology. 7.7% of all tumours expressed vimentin. Almost all of these cases (19/21) were Grade 3 invasive ductal carcinomas, and the majority (13/21) of these were associated with a ductal in situ component. Vimentin expression was also seen in the respective in situ components and correlated positively with the expression of SMA, CD10, CK 5, p53, Mib-1 and EGFR. A negative correlation was seen for the expression of CK 8/18 and the oestrogen receptor. Vimentin-expressing carcinomas revealed a significantly higher average absolute number of cytogenetic alterations per case, but a significantly lower frequency of chromosome 16q losses compared to vimentin-negative cases. Our present results demonstrate that, despite analogies between vimentin-positive breast cancers and myoepithelial cells in their expression of differentiation-related proteins, neither myoepithelial histogenesis nor EMT can exclusively explain the biology of these distinct tumours. This is mainly supported by the significantly higher incidence of vimentin-expressing breast cancers compared to any other myoepithelial breast tumours and the fact that vimentin is already observed in ductal in situ components. We therefore propose the alternative hypothesis that vimentin-expressing breast carcinomas may derive from breast progenitor cells with bilinear (glandular and myoepithelial) differentiation potential.

Relative paucity of gross genetic alterations in myoepitheliomas and myoepithelial carcinomas of salivary glands.

The diagnosis of salivary gland myoepithelioma, an entity with heterogeneous cytomorphology and inconsistent immunophenotype, rests on conventional histology. However, the clinical course cannot be predicted reliably from cytomorphological and immunophenotypic analysis. The present study determined the immunophenotype of a representative series of 12 myoepitheliomas and 21 malignant myoepitheliomas. Among the seven markers tested, antibodies against cytokeratins 5/6, S-100 protein, and vimentin produced the most consistent reactivity profile. Comparative genomic hybridization (CGH) profiles of 12 myoepitheliomas showed chromosomal losses in three of 12 cases. In myoepithelial carcinomas, however, ten of 19 tissues investigated by CGH lacked detectable cytogenetic aberrations. In five cases, aberrations involved chromosome 8, in line with observations in salivary gland carcinomas of other differentiation. One case that was represented in three separately localized manifestations of the disease proved informative as to the relevance of gross aberration for tumour development, as these tumours differed in their CGH profiles. Staining for cytokeratins 5/6 is a useful addition to the established immunohistological marker panel in the work-up of myoepitheliomas, because of its reliable expression in most cases and because it may underline the epithelial nature of the lesion. CGH proved to be of limited value as a diagnostic adjunct; the presence of numerous gross cytogenetic aberrations should raise the suspicion of malignancy. The low frequency of aberrations detectable by CGH in overtly malignant myoepithelial neoplasms suggests that gross cytogenetic alterations were acquired in the course of tumour progression and points to the relevance of genetic changes not resolved by CGH.

Methicillin-resistant Staphylococcus aureus keratitis after excimer laser photorefractive keratectomy1.

A 43-year-old woman in good health was admitted to the hospital 3 days after photorefractive keratectomy (PRK) in the left eye with postoperative bandage contact lens application. She had developed a severe keratitis with ulceration and hypopyon. Upon the patient's admission to the hospital, the contact lens was removed. Ofloxacin eyedrops were prescribed 4 times a day. In the hospital, the patient was successfully treated with immediate thermocautery application, followed by full-thickness keratoplasty the next day and intensive systemic and topical antibiotics. Cultures were positive for methicillin-resistant Staphylococcus aureus (MRSA). Severe MRSA keratitis is a rare cause of infection after PRK.