Cell Senescence-Related Pathways Are Enriched in Breast Cancer Patients With Late Toxicity After Radiotherapy and Low Radiation-Induced Lymphocyte Apoptosis.

Background: Radiation-induced late effects are a common cause of morbidity among cancer survivors. The biomarker with the best evidence as a predictive test of late reactions is the radiation-induced lymphocyte apoptosis (RILA) assay. We aimed to investigate the molecular basis underlying the distinctive RILA levels by using gene expression analysis in patients with and without late effects and in whom we had also first identified differences in RILA levels. Patients and Methods: Peripheral blood mononuclear cells of 10 patients with late severe skin complications and 10 patients without symptoms, selected from those receiving radiotherapy from 1993 to 2007, were mock-irradiated or irradiated with 8 Gy. The 48-h response was analyzed in parallel by RILA assay and gene expression profiling with Affymetrix microarrays. Irradiated and non-irradiated gene expression profiles were compared between both groups. Gene set enrichment analysis was performed to identify differentially expressed biological processes. Results: Although differentially expressed mRNAs did not reach a significant adjusted p-value between patients suffering and not suffering clinical toxicity, the enriched pathways indicated significant differences between the two groups, either in irradiated or non-irradiated cells. In basal conditions, the main differentially expressed pathways between the toxicity and non-toxicity groups were the transport of small molecules, interferon signaling, and transcription. After 8 Gy, the differences lay in pathways highly related to cell senescence like cell cycle/NF-κB, G-protein-coupled receptors, and interferon signaling. Conclusion: Patients at risk of developing late toxicity have a distinctive pathway signature driven by deregulation of immune and cell cycle pathways related to senescence, which in turn may underlie their low RILA phenotype.

Mammographic density and breast cancer in women from high risk families.

INTRODUCTION: Mammographic density (MD) is one of the strongest determinants of sporadic breast cancer (BC). In this study, we compared MD in BRCA1/2 mutation carriers and non-carriers from BRCA1/2 mutation-positive families and investigated the association between MD and BC among BRCA1/2 mutation carriers per type of mutation and tumor subtype. METHODS: The study was carried out in 1039 female members of BRCA1 and BRCA2 mutation-positive families followed at 16 Spanish Genetic Counseling Units. Participants' density was scored retrospectively from available mammograms by a single blinded radiologist using a 5-category scale (<10 %, 10-25 %, 25-50 %, 50-75 %, >75 %). In BC cases, we selected mammograms taken prior to diagnosis or from the contralateral breast, whereas, in non-cases, the last screening mammogram was evaluated. MD distribution in carriers and non-carriers was compared using ordinal logistic models, and the association between MD and BC in BRCA1/2 mutation carriers was studied using logistic regression. Huber-White robust estimators of variance were used to take into account correlations between family members. A similar multinomial model was used to explore this association by BC subtype. RESULTS: We identified and scored mammograms from 341 BRCA1, 350 BRCA2 mutation carriers and 229 non-carriers. Compared to non-carriers, MD was significantly lower among BRCA2 mutation carriers (odds ratio (OR) =0.71; P-value=0.04), but not among BRCA1 carriers (OR=0.84; P-value=0.33). MD was associated with subsequent development BC (OR per category of MD=1.45; 95 % confidence interval=1.18-1.78, P-value<0.001), with no significant differences between BRCA1 and BRCA2 mutation carriers (P-value=0.48). Finally, no statistically significant differences were observed in the association of MD with specific BC subtypes. CONCLUSIONS: Our study, the largest to date on this issue, confirms that MD is an independent risk factor for all BC subtypes in either BRCA1 and BRCA2 mutation carriers, and should be considered a phenotype risk marker in this context.

Apoptosis for prediction of radiotherapy late toxicity: lymphocyte subset sensitivity and potential effect of TP53 Arg72Pro polymorphism.

We tested apoptosis levels in in vitro irradiated T-lymphocytes from breast cancer (BC) patients with radiotherapy-induced late effects. Previous results reported in the literature were revised. We also examined the effect of TP53 Arg72Pro polymorphism on irradiation-induced apoptosis (IA). Twenty BC patients, ten with fibrosis and/or telangiectasias and ten matched controls with no late reactions, were selected from those receiving radiotherapy between 1993 and 2007. All patients were followed-up at least 6 years after radiotherapy. Using the combination of both CD3 and CD8 antibodies the in vitro IA was measured in CD3, CD8 and CD4 T-lymphocytes, and CD8 natural killer lymphocytes (CD8 NK) by flow cytometry. The TP53 Arg72Pro genotype was determined by sequencing. Patients with late radiotherapy toxicity showed less IA for all T-lymphocytes except for the CD8 NK. CD8 NK showed the highest spontaneous apoptosis and the lowest IA. IA in patients with toxicity appears to be lower than the control patients only in TP53 Arg/Arg patients (P = 0.077). This difference was not present in patients carrying at least one Pro allele (P = 0.8266). Our data indicate that late side effects induced by radiotherapy of BC are associated to low levels of IA. CD8 NK cells have a different response to in vitro irradiation compared to CD8 T-lymphocytes. It would be advisable to distinguish the CD8 NK lymphocytes from the pool of CD8+ lymphocytes in IA assays using CD8+ cells. Our data suggest that the 72Pro TP53 allele may influence the IA of patients with radiotherapy toxicity.

Risk factors associated with the occurrence of breast cancer after bilateral salpingo-oophorectomy in high-risk women.

INTRODUCTION: Bilateral salpingo-oophorectomy (BSO) is a common procedure for preventing breast and ovarian cancer in high-risk women. The goal of this study was to determine the incidence of subsequent breast cancer (BC) in a high-risk population and to identify clinical and epidemiological predictors of BC following BSO. MATERIALS AND METHODS: One hundred and thirty-three consecutive high-risk women, tested for BRCA1 and BRCA2 mutations due to family history, underwent preventive or therapeutic BSO at one of the study hospitals. One hundred and three patients had breast tissue at risk and were considered evaluable for the event-free survival analysis. Twenty-five women harbored a deleterious mutation in BRCA1 and 25 in BRCA2 genes. RESULTS: Fifteen cases of invasive BC were diagnosed with a median interval of 49 months after BSO. Multivariate analysis showed that a prior BC after 50 years of age (p=0.004), age over 50 years at the time of BSO (p=0.005), and prior replacement or contraceptive hormonal treatment (p=0.007) were significantly associated with a shorter event-free survival. CONCLUSION: In conclusion, age at prior diagnosis of cancer, age at BSO and prior hormonal treatment may be predictors of breast cancer after BSO.

Uptake of predictive testing among relatives of BRCA1 and BRCA2 families: a multicenter study in northeastern Spain.

Identifying a BRCA mutation among families with hereditary breast and ovarian cancer enables distinguishing those who may benefit from a specific medical management. This study aimed to evaluate the uptake of predictive testing among close relatives of a proband in Spanish families with a BRCA1 or BRCA2 mutation, and to determine the associated demographic and clinical predictors. A retrospective cohort of families undergoing clinical genetic testing at four university hospitals in northeastern Spain was considered. From 108 unrelated BRCA1/2 families, 765 close relatives of probands were analyzed. Sixty percent of the first-degree and 28% of the second-degree relatives underwent predictive testing within a median time of 2 and 6 months, respectively, since the mutation disclosure to the proband. Relatives undergoing genetic testing were more likely to be female, first-degree, and belong to a family with a proband who had a high educational level. Relatives were also more likely to have offspring, a previous cancer diagnosis, and to be aged between 30 and 64 years. Among second-degree relatives, having a first-degree relative with cancer was highly correlated with uptake. In conclusion, uptake of BRCA1/2 predictive testing among close relatives was notably high and within a short period of time after disclosure of the mutation to the proband. Being female, a high educational level of the proband, and having a close relative with cancer were associated with uptake among relatives. Further studies are warranted to determine whether information is disseminated properly by probands and to learn about the reasons for those not undergoing testing.