Reactive stroma and trastuzumab resistance in HER2-positive early breast cancer.

We investigated the value of reactive stroma as a predictor for trastuzumab resistance in patients with early HER2-positive breast cancer receiving adjuvant therapy. The pathological reactive stroma and the mRNA gene signatures that reflect reactive stroma in 209 HER2-positive breast cancer samples from the FinHer adjuvant trial were evaluated. Levels of stromal gene signatures were determined as a continuous parameter, and pathological reactive stromal findings were defined as stromal predominant breast cancer (SPBC; ≥50% stromal) and correlated with distant disease-free survival. Gene signatures associated with reactive stroma in HER2-positive early breast cancer (N = 209) were significantly associated with trastuzumab resistance in estrogen receptor (ER)-negative tumors (hazard ratio [HR] = 1.27 p interaction = 0.014 [DCN], HR = 1.58, p interaction = 0.027 [PLAU], HR = 1.71, p interaction = 0.019 [HER2STROMA, novel HER2 stromal signature]), but not in ER-positive tumors (HR = 0.73 p interaction = 0.47 [DCN], HR = 0.71, p interaction = 0.73 [PLAU], HR = 0.84; p interaction = 0.36 [HER2STROMA]). Pathological evaluation of HER2-positive/ER-negative tumors suggested an association between SPBC and trastuzumab resistance. Reactive stroma did not correlate with tumor-infiltrating lymphocytes (TILs), and the expected benefit from trastuzumab in patients with high levels of TILs was pronounced only in tumors with low stromal reactivity (SPBC <50%). In conclusion, reactive stroma in HER2-positive/ER-negative early breast cancer tumors may predict resistance to adjuvant trastuzumab therapy.

Utilizing fluorescent life time imaging microscopy technology for identify carriers of BRCA2 mutation.

Worldwide, more than one million women are diagnosed with breast cancer every year, making it the most common female malignancy in the developed world. Germline mutations in BRCA1 and BRCA2 genes are estimated to increase the risk for developing breast cancer by up to 87%. From a clinical point of view, identification of BRCA1 and BRCA2 mutation carriers offers an opportunity to early identify or prevent the development of malignancy; therefore the ability to determine which women are more likely to carry BRCA1 or BRCA2 mutations is of great importance. The available diagnostic tests for mutation analysis of BRCA1 and BRCA2 are time- and labor-intensive, expensive, and do not allow the identification of all the functional mutations. We utilized the Fluorescent lifetime (FLT) imaging microscopy method which allows recognizing different cell populations, in order to distinguish between lymphocytes from BRCA1 and BRCA2 mutation carriers and non-carrier women by using easily obtainable lymphocyte cells from peripheral blood. Our results demonstrate that cells originated from BRCA2-mutation carriers have significantly lower FLT values compared with BRCA1 mutation carriers and control cells. This simple, inexpensive and sensitive method may be utilized in the future to detect BRCA2 mutation carriers, particularly those bearing unknown functional mutations.

VennBLAST­whole transcriptome comparison and visualization tool.

RNA-seq is the method of choice for getting a primary list of genes for non-model organisms. Once this is achieved, one would proceed to annotate the newly discovered genes and consequently strive to position the organism in an evolutionary context. These kinds of studies involving high-throughput sequencing generate large amounts of data, whose analysis might be time consuming for the non-specialist user and merit computational skills. Here we describe VennBLAST, a set of high-performance utilities that combines fast parallelized BLAST filtering with a visualization tool for whole-transcriptomic alignment comparison using Venn diagrams. The software accurately illustrates simple set relationships between numbers of matching sequences and identifies transcriptome conservation among different organisms. The intuitive Venn diagram visualization allows researchers to easily select a desired subset of genes for further inspection, using the DAVID functional annotation tools, for instance, which enables investigators to understand biological meaning behind large lists of genes.

[Tumor, metastasis and what's in between].

Cancer is a major factor of morbidity and mortality worldwide. Over 90% of cancer-related deaths are due to metastatic disease. Observations made more than 140 years ago described cancer cells from solid tumors in the bloodstream. yet, the significance of these circulating and disseminated cells and their contribution to the generation of metastasis remained a mystery. Recently, substantial technological advances have enabled the detection and isolation of circulating tumor cells from the peripheral blood. Currently, this technology allows quantitative analysis of circulating cancer cell content and permits a view of the genetic and phenotypic changes in this accessible population. In the future, researchers hope to use circulating tumor cells as a powerful tool for early detection, prognosis, tumor response assessment and even for treatment selection. The discovery of cancer cells in the bloodstream holds many promises in the study, diagnosis and treatment of cancer, but, at the same time, raises difficult questions regarding the identity of these cells, their contribution to the process of metastasis and their ability to aid medical decisions. This review aims to introduce the topic of circulating tumor cells to the Israeli medical community and encourage active participation in basic and translational research in this field. We believe this field holds great potential for promoting the practice of surgical oncology, tumor surveillance and clinical oncology.

Prognostic Factors in Advanced Adrenocortical Carcinoma: Summary of a National Referral Center's 20 years of Experience.

Context: Adrenocortical carcinoma (ACC) is a rare malignancy with poor prognosis for both locally advanced and metastatic disease. Standard treatment with combination etoposide-doxorubicin-cisplatin-mitotane (EDP-M) is highly toxic and some patients benefit from mitotane monotherapy. However, identification of these patients remains challenging. Objective: We present a summary of the Israeli national referral center's 20 years of experience in treating advanced ACC, with the aim of identifying prognostic factors and assisting in treatment decision making. Methods: We conducted a retrospective multivariate analysis of patients treated for metastatic or locally advanced ACC at Hadassah Medical Center between 2000 and 2020 to determine clinical, pathological, and treatment factors correlated with overall survival (OS). Results: In our cohort of 37 patients, a combination of modified European Network for the study of Adrenal Tumors (mENSAT) staging with either grade and R status, or age and symptoms was validated to stratify prognosis (P = .01 and P = .03, respectively). Patients who underwent R0 resection followed by radiotherapy or metastasectomy for oligometastatic disease had longer OS than patients with residual disease: median OS of 55 months vs 14 months, respectively, hazard ratio 3.1 (CI 1.4-6.7, P = .005). Patients treated with mitotane monotherapy had a significantly better prognosis, yet this result was attenuated in a multivariate analysis controlling for mENSAT and R status. Of patients treated with EDP-M, 41.4% experienced grade 3 or higher adverse events. Conclusion: Patients with advanced ACC achieving R0 status have a better prognosis and might benefit from mitotane monotherapy.

Glucagonoma and the glucagonoma syndrome - cumulative experience with an elusive endocrine tumour.

OBJECTIVE: Glucagonoma is a pancreatic neuroendocrine tumour that arises from alpha cells in the pancreas and is often accompanied by a characteristic clinical syndrome. DESIGN: In this report, we present the cumulative experience and clinical characteristics of six patients diagnosed with glucagonoma and the glucagonoma syndrome and treated at our centre during the past 25 years. RESULTS: Although the course of the disease was variable, some features were similar. The median age at diagnosis was 53·5 years; the median time from onset of symptoms to diagnosis was 39 months. Presenting symptoms were as follows: weight loss 5/6 (83%), necrotizing migratory erythema (NME) 5/6 (83%), diabetes mellitus 4/6 (66%) and diarrhoea, weakness and thrombosis 2/6 (33%). Plasma glucagon was elevated in all patients upon diagnosis (range 200-10,000 pm; N < 50). Skin biopsy was diagnostic only in 1/6 specimens obtained, even after revision. Metastatic disease developed in all patients; 4/6 initially presented with hepatic metastasis. All patient symptoms responded to somatostatin analogue therapy. In 4/6, the NME responded to amino acid solutions. Other modes of therapy were as follows: surgery in 3/6 patients, peptide receptor radioligand therapy with (90) Y-DOTATOC (PRRT) in 3/6 patients (two responses) and chemotherapy in three patients (two responded). Four out of six patients died of the disease, and median survival time was 6·25 years (range 2-11) from diagnosis and 8 years (range 8-16) from initial symptoms. Five-year survival was 66%. CONCLUSION: Our data indicate that somatostatin analogues and an aggressive surgical approach offer symptom relief and tumour control. Among other available treatment modalities, PRRT seems to hold the most promise.

Heparanase: a potential marker of worse prognosis in estrogen receptor-positive breast cancer.

Heparanase promotes tumor growth in breast tumors. We now evaluated heparanase protein and gene-expression status and investigated its impact on disease-free survival in order to gain better insight into the role of heparanase in ER-positive (ER+) breast cancer prognosis and to clarify its role in cell survival following chemotherapy. Using pooled analysis of gene-expression data, we found that heparanase was associated with a worse prognosis in estrogen receptor-positive (ER+) tumors (log-rank p < 10-10) and predictive to chemotherapy resistance (interaction p = 0.0001) but not hormonal therapy (Interaction p = 0.62). These results were confirmed by analysis of data from a phase III, prospective randomized trial which showed that heparanase protein expression is associated with increased risk of recurrence in ER+ breast tumors (log-rank p = 0.004). In vitro experiments showed that heparanase promoted tumor progression and increased cell viability via epithelial-mesenchymal transition, stemness, and anti-apoptosis pathways in luminal breast cancer. Taken together, our results demonstrated that heparanase is associated with worse outcomes and increased cell viability in ER+ BC.

[Adrenocortical carcinoma].

Adrenocortical carcinoma (ACC) is a rare cancer with a generally poor prognosis. In approximately 60% of cases the initial clinical manifestations are due to hypersecretion of adrenocortical hormones. Cushing's syndrome is the most frequent hormonal manifestation. In the remainder of the cases the tumor is identified after imaging procedures for nonspecific complaints such as abdominal pain and nausea. Medical therapy is employed in patients with unresectable or partially resected tumor and metastatic disease. The current accepted treatment is a combination of Mitotane with chemotherapy, aimed at controlling hormonal hypersecretion and reduction of tumor mass. In ACC patients there is wide variability in the course of the disease: some with metastatic disease will survive for more than 10 years, others succumb to the disease within months.

What variables are associated with the public's willingness to take measures to maintain a hygienic hospital environment?

BACKGROUND: Most of the studies on hospital infections have focused on the perceptions and reported behavior of the medical personnel. This research explore the practices undertaken both by Israeli patients and visitors, in order to maintain a hygienic hospital environment, and to locate the variables that are associated with them. METHODS: An online survey of national representative sample of Israeli hospital's visitors and patients adult population, who were hospitalized in the five years before the interview (n=209), and who visited patients in hospitals in the three years before the interview (n=454). RESULTS: Only a minority of patients (24%) comment to medical personnel about maintaining hygiene, while a majority (67%-69%) took active steps to maintain a hygienic environment. The main variables that were found to be associated with patients' making comments were level of religiousness and gender, whereas priorities, namely whether hospital infections were a high priority, and the frequency of the patient's visits to hospital outpatient clinics, were associated with self-initiated action. CONCLUSIONS: In order to reduce barriers to commenting to hospital personnel, we propose framing the subject of hospital hygiene as a matter of health literacy and a subject of public discourse, rather than a sole medical issue.

Predictive power of the post-treatment scans after the initial or first two courses of [177Lu]-DOTA-TATE.

BACKGROUND: The aim of this study was to evaluate the predictive power of the absorbed dose to kidneys after the first course of treatment with [177Lu]-DOTA-TATE for neuroendocrine tumors (NETs) on the cumulative kidney absorbed dose after 3 or 4 cycles of treatment. Post-treatment scans (PTS) are acquired after each cycle of peptide receptor radionuclide therapy (PRRT) with [177Lu]-DOTA-TATE for personalized radiation dosimetry in order to ensure a cumulative absorbed dose to kidneys under a safety threshold of 25 Gy. One hundred eighty-seven patients who completed treatment with [177Lu]-DOTA-TATE and underwent PTS for dosimetry calculation were included in this retrospective study. The correlation between the cumulative absorbed dose to kidneys after the completion of treatment and the absorbed dose after the first cycle(s) was studied. Multilinear regression analysis was done to predict the cumulative absorbed dose to the kidneys of the subsequent cycles, and an algorithm for the follow up of kidney absorbed dose is proposed. RESULTS: Patients whose absorbed dose to kidneys after the first cycle of treatment is below 5.6 Gy can receive four cycles of treatment with a cumulative dose less than 25 Gy (p < 0.1). For the other patients, the cumulative absorbed dose after 3 or 4 cycles of treatment can be predicted after the second cycle of treatment to allow for an early decision regarding the number of cycles that may be given. CONCLUSIONS: The follow up of kidney absorbed dose after PRRT can be simplified with the algorithm presented in this study, reducing by one-third the number of post-treatment scans and reducing hospitalization time for more than half of the treatment cycles.

SYK expression level distinguishes control from BRCA1-mutated lymphocytes.

BACKGROUND: About 5%-10% of breast cancer and 10%-15% of ovarian cancer are hereditary. BRCA1 and BRCA2 are the most common germline mutations found in both inherited breast and ovarian cancers. Once these mutations are identified and classified, a course of action to reduce the risk of developing either ovarian or breast cancer - including surveillance and surgery - is carried out. PURPOSE: The purpose of the current research is to characterize the gene expression differences between healthy cells harboring a mutation in BRCA1/2 genes and normal cells. This will allow detection of candidate genes and help identify women who carry functional BRCA1/2 mutations, which cannot always be detected by the available sequencing methods, for example, carriers of mutations found in regulatory sequences of the genes. MATERIALS AND METHODS: Our cohort consisted of 50 healthy women, of whom 24 were individuals with BRCA1 or BRCA2 heterozygous mutations and 26 were non-carrier controls. RNA purified from non-irradiated lymphocytes of nine BRCA1/2 mutation carriers versus four control mutation-negative individuals was utilized for RNA-Seq analysis. The selected RNA-Seq transcripts were validated, and the levels of spleen tyrosine kinase (SYK) mRNA were measured by using real-time quantitative polymerase chain reaction. RESULTS: Differences in gene expression were found when comparing untreated lymphocytes of BRCA1/2 mutation carriers and controls. Among others, the SYK gene was identified as being differently expressed for BRCA1/2 mutation carriers. The expression level of SYK was significantly higher in untreated healthy lymphocytes of BRCA1 heterozygote carriers compared with controls, regardless of irradiation. In contrast to normal tissues, in cancerous breast tissues, the expression levels of the BRCA1 and SYK genes were not intercorrelated. CONCLUSION: Collectively, our observations demonstrate that SYK may prove to be a good candidate for better diagnosis, treatment, and prevention of BRCA1 mutation-associated breast cancer.

Beyond the hospital infection control guidelines: a qualitative study using positive deviance to characterize gray areas and to achieve efficacy and clarity in the prevention of healthcare-associated infections.

Background: The literature is replete with attempts to design and promote customized guidelines to reduce infections during the care continuum. Paradoxically, these efforts sometimes result in gray areas where many staff members are unaware of what is required of them, which then leads to confusion, frustration, and uncertainty.We coined the phrase "gray areas" in this context to encompass the variety of situations on the care continuum that are not addressed in the accepted guidelines, and where staff members are unsure of how to proceed.The purpose of the present study was to characterize the gray areas that were reported by staff and to identify the practices of Positive Deviance (PD) individuals. We define to PD individuals as people who independently develop creative solutions to solve problems not identified by the majority in their community. Methods: A qualitative constructivist research methodology was used that included personal interviews, observations and video recordings of identified PD practices to enhance infection control. The study was conducted January through March 2018, in two Intensive Care Units (ICU) units at Hadassah Hospital, Jerusalem, Israel. Personal interviews were conducted with 82 staff members from the General ICU (GICU) and Medical ICU (MICU). Results: The study confirmed that guidelines cannot cover all the different situations that arise during the care continuum and can paradoxically result in the increased spread of hospital infections. Our study found there are numerous individuals who independently develop and implement solutions for gray areas. The creative and practical solutions of PD individuals can address the barriers and difficulties on the care continuum that were encountered by the staff in their communities. For example, inserting a central venous line is a complex practice in the general guidelines, while the PDs provided clear situation-specific solutions not covered in the guidelines. Conclusions: The recommendations of the present study are to encourage hospital personnel to create their own solutions for various situations on the care continuum, and to disseminate them within their units to achieve a bottom up change, in lieu of investing in new or specific written guidelines.

p-STAT3 in luminal breast cancer: Integrated RNA-protein pooled analysis and results from the BIG 2-98 phase III trial.

In the present study, in order to investigate the role of signal transducer and activator of transcription 3 (STAT3) in estrogen receptor (ER)-positive breast cancer prognosis, we evaluated the phosphorylated STAT3 (p-STAT3) status and investigated its effect on the outcome in a pooled analysis and in a large prospective adjuvant trial. By using the TCGA repository, we developed gene signatures that reflected the level of p-STAT3. Using pooled analysis of the expression data from luminal breast cancer patients, we assessed the effects of the p-STAT3 expression signature on prognosis. We further validated the p-STAT3 prognostic effect using immunohistochemistry (IHC) and immunofluorescence staining of p-STAT3 tissue microarrays from a large randomised prospective trial. Our analysis demonstrated that p-STAT3 expression was elevated in luminal A-type breast cancer (Kruskal-Wallis test, P<10e-10) and was significantly associated with a good prognosis (log-rank, P<10e-10). Notably, the p-STAT3 expression signature identified patients with a good prognosis irrespective of the luminal subtype (log-rank: luminal A, P=0.026; luminal B, P=0.006). p-STAT3 staining by IHC in the stroma or tumour was detected in 174 out of 610 ER-positive samples (28.5%) from the BIG 2-98 randomised trial. With a median follow-up of 10.1 years, p-STAT3 was associated with a reduced risk of recurrence in ER-positive/HER2-negative breast cancer (Cox univariate HR, 0.66; 95% CI, 0.44-0.98; P=0.04). On the whole, our data indicate that p-STAT3 is associated with an improved outcome in ER-positive breast cancer.

The role of imatinib mesylate (Glivec) for treatment of patients with malignant endocrine tumors positive for c-kit or PDGF-R.

Imatinib mesylate (IM), a small molecule that is a selective inhibitor of the ABL, platelet derived growth factor receptor (PDGFR-R) and stem cell ligand receptor (c-kit) tyrosine kinases (TK). IM was also found to inhibit the TK activity of BCR/ABL fusion protein produced in chronic myelogenous leukemia, with marked clinical activity against the disease. Since both PDGF-R and c-kit both having a putative role in tumorigenesis, we investigated the efficacy and safety of the use of IM in patients with endocrine tumors unresponsive to conventional therapies that expressed c-kit and/or PDGF-R (within the framework of a comprehensive phase II multi-center study of IM in patients with solid tumors). IM was initiated at a dose of 400 mg/day, with possible dose escalation within 1 week to 600 mg/day and an option to raise the dose to 800 mg/day in the event of progression and in the absence of safety concerns for a period of up to 12 months. Between September 2002 and July 2003, 15 adult patients with disseminated endocrine tumors were recruited as follows: medullary thyroid carcinoma (MTC, n = 6); adrenocortical carcinoma (ACC, n = 4); malignant pheochromocytoma (pheo, n = 2); carcinoid (non-secreting, n = 2), neuroendocrine tumor (NET, n = 1). No objective responses were observed. MTC--disease progression in 4 patients, and treatment discontinuation in 2 patients due to adverse events; ACC--disease progression in 3 patients, and treatment discontinuation in 1 patient due to severe psychiatric adverse event; Pheo--disease progression in 2 patients; Carcinoid--stable disease in 1 patient (6.5 months), and disease progression in 1 patient; NET--disease progression in 1 patient. IM does not appear to be useful for treatment of malignant endocrine tumors, also causing significant toxicity in this patient population.

Sorafenib treatment during partial hepatectomy reduces tumorgenesis in an inflammation-associated liver cancer model.

The long-term prognosis after resection of hepatocellular carcinoma (HCC), which is one of the treatment options for early-stage HCC, remains unsatisfactory as a result of a high incidence of disease recurrence. Recent studies performed in murine models revealed a link between liver regeneration under chronic inflammation and hepatic tumorigenesis. Sorafenib is a potent drug for advanced HCC with multikinase inhibition activity. We propose that inhibition of signal transduction pathways which are activated during hepatectomy, using Sorafenib, will reduce accelerated tumorigenesis. To test this hypothesis, we studied the Mdr2-knockout (KO) mouse strain, a model of inflammation-associated cancer, which underwent partial hepatectomy (PHx) at three months of age, with or without Sorafenib.Here we show that Sorafenib treatment during PHx inhibited different signal transduction pathways at the multikinase levels, but did not result in increased morbidity or mortality. At the early stages after PHx, Sorafenib treatment had no effect on the course of proliferation, apoptosis and DNA repair in the regenerating liver, but resulted in decreased stellate cells activation and inflammatory response. Finally, we show that Sorafenib treatment during PHx at three months of age resulted in decreased fibrosis and tumor formation at 8.5 months.In conclusion our study indicates that short-term Sorafenib treatment during PHx is safe and effective in inhibiting inflammation-associated cancer, and is therefore a potential strategy for recurrence prevention in patients with early-stage HCC treated with PHx.

Pancreatic neuroendocrine tumors with transformation to insulinoma: an unusual presentation of a rare disease.

UNLABELLED: Approximately 35% of the pancreatic neuroendocrine tumors (pNETs) are functional, the most common of which is an insulinoma. Rarely can initially nonfunctioning tumor undergo biological transformation to a hormone-secreting tumor with subsequent changes in the clinical picture. We present here three unique patients with long-standing pNETs who developed life-threatening hyperinsulinemic hypoglycemia along with tumor progression. In two of the patients, everolimus (Afinitor) was administered in an attempt to control both tumor growth and hypoglycemia. In two cases everolimus therapy resulted in the abolishment of hypoglycemia and induced significant tumor regression; however these beneficial responses were transient. These cases highlight the exceptional ability of pNETs to change biological behavior in parallel with disease progression. Our experience concurs with recently published studies demonstrating the utility of everolimus for the control of both hypoglycemia and tumor progression. LEARNING POINTS: Nonfunctional pNET can gain new features such as insulin secretion with related morbidity.Gain of function in a previously nonfunctional pNET signifies tumor progression and is usually associated with poor prognosis.Everolimus proved to be a viable treatment for hypoglycemia in insulinoma patients and was also proven highly effective in the patients presented here.As disease progresses, the effect of everolimus on hypoglycemia wanes. We report for the first time the development of hypoglycemia during everolimus treatment.

A phase 1/2 of a combination of cetuximab and taxane for "triple negative" breast cancer patients.

50-70% of tumors of the so called "triple negative" subtype of breast cancer express EGFR. We hypothesized that addition of anti EGFR to Taxanes will result in increased effectiveness in EGFR expressing tumors. Here we set out to obtain data regarding the safety, tolerability and also the effectivity of the combination of weekly Taxane treatments with Cetuximab -an anti EGFR antibody in this subgroup of breast cancer. 18 triple negative breast cancer patients were treated with weekly Cetuximab and Taxane therapy. Addition of Cetuximab resulted in controllable Dermatologic toxicity in most patients -with grade 3 in two patients. Some impressive results were noted including one CR, one near CR and regression of chemotherapy and radiation resistance skin metastasis. Median TTF -and overall survival -6 and 12 months. Administration of Taxane Cetuximab weekly therapy for triple negative breast cancer patients is feasible. Use of anti EGFR-Taxane combinations should be assessed in larger clinical trials in this patient population perhaps in a similar manner to the lung cancer patients only in those with strong EGFR expression.

Pregnancy in a patient with adrenal carcinoma treated with mitotane: a case report and review of literature.

CONTEXT: Adrenocortical carcinoma (ACC) affects patients in a broad age group, including young women. Mitotane, an adrenolytic agent, is the mainstay of treatment after surgical removal of the tumor. There is extreme paucity of information regarding the effect of mitotane on childbearing potential and pregnancy outcome. OBJECTIVE: The aim of the study was to describe and discuss the case of an ACC patient who conceived while on mitotane treatment. Current literature is reviewed. PATIENT AND METHODS: A 33-year-old woman received mitotane treatment for 4 years due to metastatic ACC. Despite nearly therapeutic blood levels of the drug, the patient had regular menstruation and was able to conceive. Mitotane was stopped at gestation week 6. Although the drug continued to be detected in considerable amounts, the fetus developed normally, including morphologically intact adrenal glands. At gestation week 21, pregnancy was terminated due to ACC recurrence. Mitotane levels were undetectable in fetal cord blood and amniotic fluid. CONCLUSION: Our report suggests that mitotane, despite its action as an endocrine disruptor, does not affect normal gonadal function or an ability to conceive. The concern of placental transfer by this hydrophobic compound is not supported by our findings. However, we do not recommend drawing conclusions regarding the safety of mitotane in pregnancy, based on 1 or several case reports. Until more data are available, pregnancy should be avoided in women being treated with mitotane for ACC.

Determination of molecular markers for BRCA1 and BRCA2 heterozygosity using gene expression profiling.

Approximately 5% of all breast cancers can be attributed to an inherited mutation in one of two cancer susceptibility genes, BRCA1 and BRCA2. We searched for genes that have the potential to distinguish healthy BRCA1 and BRCA2 mutation carriers from noncarriers based on differences in expression profiling. Using expression microarrays, we compared gene expression of irradiated lymphocytes from BRCA1 and BRCA2 mutation carriers versus control noncarriers. We identified 137 probe sets in BRCA1 carriers and 1,345 in BRCA2 carriers with differential gene expression. Gene Ontology analysis revealed that most of these genes relate to regulation pathways of DNA repair processes, cell-cycle regulation, and apoptosis. Real-time PCR was conducted on the 36 genes, which were most prominently differentially expressed in the microarray assay; 21 genes were shown to be significantly differentially expressed in BRCA1 and/or BRCA2 mutation carriers as compared with controls (P < 0.05). On the basis of a validation study with 40 mutation carriers and 17 noncarriers, a multiplex model that included six or more coincidental genes of 18 selected genes was constructed to predict the risk of carrying a mutation. The results using this model showed sensitivity 95% and specificity 88%. In summary, our study provides insight into the biologic effect of heterozygous mutations in BRCA1 and BRCA2 genes in response to ionizing irradiation-induced DNA damage. We also suggest a set of 18 genes that can serve as a prediction and screening tool for BRCA1 or BRCA2 mutational carriers by using easily obtained lymphocytes.