Control of mitochondrial redox balance and cellular defense against oxidative damage by mitochondrial NADP+-dependent isocitrate dehydrogenase

Mitochondria are the major organelles that produce reactive oxygen species (ROS) and the main target of ROS-induced damage as observed in various pathological states including aging. Production of NADPH required for the regeneration of glutathione in the mitochondria is critical for scavenging mitochondrial ROS through glutathione reductase and peroxidase systems. We investigated the role of mitochondrial NADP(+)-dependent isocitrate dehydrogenase (IDPm) in controlling the mitochondrial redox balance and subsequent cellular defense against oxidative damage. We demonstrate in this report that IDPm is induced by ROS and that decreased expression of IDPm markedly elevates the ROS generation, DNA fragmentation, lipid peroxidation, and concurrent mitochondrial damage with a significant reduction in ATP level. Conversely, overproduction of IDPm protein efficiently protected the cells from ROS-induced damage. The protective role of IDPm against oxidative damage may be attributed to increased levels of a reducing equivalent, NADPH, needed for regeneration of glutathione in the mitochondria. Our results strongly indicate that IDPm is a major NADPH producer in the mitochondria and thus plays a key role in cellular defense against oxidative stress-induced damage.

Ethanol induces CYP2E1 by protein stabilization. Role of ubiquitin conjugation in the rapid degradation of CYP2E1

In the present study, we demonstrate that ethanol induces CYP2E1 by protein stabilization in vivo. The control half-life of CYP2E1 was determined to be 6-7 h followed by a slower secondary phase. The half-life of ethanol-stabilized CYP2E1 was calculated to be 38 h. The mechanism underlying the rapid degradation of CYP2E1 was also investigated and appears to involve the ubiquitin-proteasome proteolytic pathway. An in vitro assay using the cytosolic fraction was developed to further characterize CYP2E1 degradation. Using this assay, 40-50% loss of CYP2E1 was observed in 1 h, coincident with the formation of high M(r) ubiquitin-CYP2E1 conjugates. At concentrations approximating those found in vivo, ethanol protects CYP2E1 from cytosolic degradation. No loss of CYP2B1/2 was observed under identical conditions, suggesting that this reaction is specific for certain P-450s which are rapidly turned over.

Stabilization of cytochrome P450j messenger ribonucleic acid in the diabetic rat

Cytochrome P450j, an enzyme involved in nitrosamine metabolism, is expressed in hepatic, pulmonary, and renal tissues and its level is elevated in ethanol- and acetone-treated rats as well as in diabetic rats induced by either streptozotocin or alloxan. Although P450j protein is substantially elevated by all inducing regimens, only in diabetic rats is P450j mRNA increased 10-fold. Nuclear run-on transcription analysis showed that this mRNA increase is not due to transcriptional activation but is due to specific stabilization of the P450j mRNA.

Breast Cancer Screening With Mammography Plus Ultrasonography or Magnetic Resonance Imaging in Women 50 Years or Younger at Diagnosis and Treated With Breast Conservation Therapy

Importance

Younger women (aged ≤50 years) who underwent breast conservation therapy may benefit from breast magnetic resonance imaging (MRI) screening as an adjunct to mammography.

Objective

To prospectively determine the cancer yield and tumor characteristics of combined mammography with MRI or ultrasonography screening in women who underwent breast conservation therapy for breast cancers and who were 50 years or younger at initial diagnosis.

Design, Setting, and Participants

This multicenter, prospective, nonrandomized study was conducted from December 1, 2010, to January 31, 2016, at 6 academic institutions. Seven hundred fifty-four women who were 50 years or younger at initial diagnosis and who had undergone breast conservation therapy for breast cancer were recruited to participate in the study. Reference standard was defined as a combination of pathology and 12-month follow-up.

Interventions

Participants underwent 3 annual MRI screenings of the conserved and contralateral breasts in addition to mammography and ultrasonography, with independent readings.

Main Outcomes and Measures

Cancer detection rate, sensitivity, specificity, interval cancer rate, and characteristics of detected cancers.

Results

A total of 754 women underwent 2065 mammograms, ultrasonography, and MRI screenings. Seventeen cancers were diagnosed, and most of the detected cancers (13 of 17 [76%]) were stage 0 or stage 1. Overall cancer detection rate (8.2 vs 4.4 per 1000; P = .003) or sensitivity (100% vs 53%; P = .01) of mammography with MRI was higher than that of mammography alone. After the addition of ultrasonography, the cancer detection rate was higher than that by mammography alone (6.8 vs 4.4 per 1000; P = .03). The specificity of mammography with MRI or ultrasonography was lower than that by mammography alone (87% or 88% vs 96%; P < .001). No interval cancer was found.

Conclusions and Relevance

After breast conservation therapy in women 50 years or younger, the addition of MRI to annual mammography screening improves detection of early-stage but biologically aggressive breast cancers at acceptable specificity. Results from this study can inform patient decision making on screening methods after breast conservation therapy.

Truncated form of importin alpha identified in breast cancer cell inhibits nuclear import of p53

Disruption of the function of tumor suppressor proteins occasionally can be dependent on their subcellular localization. In about 40% of the breast cancer tissues, p53 is found in the cytoplasm as opposed to the nucleus, where it resides in normal breast cells. This means that the regulation of subcellular location of p53 is an important mechanism in controlling its function. The transport factors required for the nuclear export of p53 and the mechanisms of their nuclear export have been extensively characterized. However, little is known about the mechanism of nuclear import of p53. p53 contains putative nuclear localization signals (NLSs) which would interact with a nuclear transport factor, importin alpha. In this report we demonstrate that importin alpha binds to NLSI in p53 and mediates the nuclear import of p53. Reverse transcriptase-polymerase chain reaction and sequencing analyses showed that a truncated importin alpha deleted the region encoding the putative NLS-binding domain of p53, suggesting that it could not bind to NLSs of p53 proteins. Binding of importin alpha to p53 was confirmed by using yeast two-hybrid assay. When expressed in CHO-K1 cells, the truncated importin alpha predominantly localized to the cytoplasm. In truncated importin alpha expressing cells, p53 preferentially localized to cytoplasmic sites as well. A significant increase in the p21(waf1/cip1) mRNA level and induction of apoptosis were also observed in importin alpha overexpressing cells. These results strongly suggest that importin alpha functions as a component of the NLS receptor for p53 and mediates nuclear import of p53.

Selective activation of the c-Jun N-terminal protein kinase pathway during 4-hydroxynonenal-induced apoptosis of PC12 cells

The by-product of lipid peroxidation, 4-hydroxynonenal (HNE), was shown to cause apoptosis in PC12 cells. In this study, we investigated the molecular mechanism of HNE-induced apoptosis in these cells. Specifically, we determined the effect of HNE on the activities of mitogen-activated protein (MAP) kinases involved in early signal transduction. Within 15 to 30 min after HNE treatment, c-Jun N-terminal protein kinase (JNK) was maximally activated, before it returned to control level at 1 h post-treatment. In contrast, activities of extracellular signal-regulated kinase and p38 MAP kinase remained unchanged from their baseline levels. Stress-activated protein kinase kinase (SEK1), an upstream kinase of JNK, was also activated within 5 min after HNE treatment and remained activated for up to 60 min. Marked activation of the JNK pathway through SEK1 and apoptosis signal-regulating kinase 1 (ASK1), an upstream kinase of SEK1, was demonstrated by the transient transfection of cDNA for wild-type SEK1 or ASK1 together with JNK into COS-7 cells. Furthermore, significant reductions in JNK activation and HNE-induced cell death were observed when either of the dominant negative mutant of SEK1 or ASK1 was cotransfected with JNK. Pretreatment of PC12 cells with a survival-promoting agent, 8-(4-chlorophenylthio)-cAMP, prevented both the HNE-induced JNK activation and apoptosis. Nonaldehyde, a nontoxic aldehyde, neither caused apoptosis nor JNK activation. Pretreatment of PC12 cells with SB203580, a specific inhibitor of p38 MAP kinase, had no effect on HNE-induced apoptosis. All these data suggest that the selective JNK activation by HNE is critical for the apoptosis of PC12 cells and that the HNE-mediated apoptosis is likely to be mediated through the activation of the ASK1-SEK1-JNK pathway without activation of extracellular signal-regulated kinase or p38 MAP kinase.

Cytochrome P450IIE1 is elevated in lymphocytes from poorly controlled insulin-dependent diabetics

Cytochrome P450IIE1, a member of the cytochrome P450 supergene family, was measured in peripheral lymphocytes of 14 patients with insulin-dependent diabetes mellitus who were in poor metabolic control, as evidenced by elevated hemoglobin A1 levels (mean, 11.9 +/- 2.8%; normal, less than 7.8). Only one major form (mol wt, 48,000 daltons) of cytochrome P450IIE1 was detected with a specific polyclonal antibody against P450IIE1. Levels of cytochrome P450IIE1 were very low to undetectable in human lymphocytes from seven normal subjects. However, levels of P450IIE1 were elevated in lymphocytes from patients with insulin-dependent diabetes mellitus. Elevated levels of cytochrome P450IIE1 determined by immunoblot analysis correlate positively with the levels of hemoglobin A1 (r = 0.8), a metabolic indicator in diabetic subjects. In one study subject in whom diabetic control was improved, the drop in hemoglobin A1C levels was accompanied by normalization of P450IIE1 levels.

Induction of CYP2E1 in liver, kidney, brain and intestine during chronic ethanol administration and withdrawal: evidence that CYP2E1 possesses a rapid phase half-life of 6 hours or less

Controversy exists as to whether the induction of CYP2E1 by ethanol occurs via increased protein synthesis or protein stabilization. To address these issues in vivo, we chronically administered ethanol to rats and determined levels of immunoreactive CYP2E1 in liver, kidney, brain and upper gastro-intestinal tract (GI). Our data shows that chronic ethanol administration induces hepatic (5-6-fold over pair-fed controls) and extra-hepatic CYP2E1, an effect which is strikingly absent 12 hours after ethanol withdrawal. No changes in CYP2E1 mRNA were observed at any time, suggesting these changes are mainly post-translational at a blood ethanol concentration of 0.15% w/v. Our experimental data indicates that CYP2E1 possesses a half-life of 6 hours or less in the liver and is rapidly degraded following the removal of ethanol. This pattern of CYP2E1 turnover was also observed in other tissues, suggestive of a similar mode of regulation.

Induction of brain cytochrome P-450IIE1 by chronic ethanol treatment

Cytochrome P-450 mediated metabolism is potentially involved in the expression of the pharmacological and/or toxicological effects of a wide variety of drugs and environmental chemicals upon tissues which contain this metabolic system. In the present investigation, the presence of cytochrome P-450IIE1 and associated mono-oxygenase activities in brain and the effect of chronic ethanol treatment on brain cytochrome P-450 (P-450) were studied. Aniline hydroxylase, N-nitroso-dimethylamine N-demethylase and p-nitrophenol hydroxylase activities (known to be mediated by P-450IIE1) were detectable in brain microsomes from untreated rats and were about 5%, 125% and 8.3%, respectively, of the corresponding hepatic levels. Chronic ethanol treatment resulted in induction of the above enzyme activities in brain microsomes by 243%, 496% and 155%, respectively. Intake of ethanol for a prolonged period also resulted in the induction of total P-450 in the brain (150% of the control). Addition of the antisera raised against rat liver cytochrome P-450IIE1 markedly inhibited brain microsomal p-nitrophenol hydroxylase activity. Immunoblot analysis of rat brain microsomes using the above antisera also revealed the induction of brain cytochrome P-450IIE1 following chronic ethanol administration. Immunocytochemical localization of cytochrome P-450IIE1 using the above antisera, revealed the preferential localization of the enzyme in the neuronal cell bodies in the cortex, hippocampus, basal ganglia, hypothalamic nuclei and reticular nuclei in the brainstem of rats treated chronically with ethanol. Based upon these studies, it is conceivable that chronic alcohol ingestion could enhance the sensitivity of certain regions of the brain to environmental chemicals that are metabolized to more toxic derivatives by the P-450 system.

Histogram analysis of apparent diffusion coefficient at 3.0t: Correlation with prognostic factors and subtypes of invasive ductal carcinoma

PURPOSE

To evaluate apparent diffusion coefficient (ADC) histogram parameters that show correlations with prognostic factors and subtypes of breast cancer.

MATERIALS AND METHODS

At 3.0T, various ADC histogram parameters were calculated including the entire tumor volume in 173 invasive ductal carcinomas: the minimum, 10th percentile, mean, median, 90th percentile, and maximum. ADC parameters were correlated with prognostic factors and subtype.

RESULTS

The mean ADCmedian value was significantly higher in the group with lymph node metastasis, HER2 positivity, and a Ki-67 value <14% than in the group with negativity for lymph node metastasis, HER2 negativity, and a Ki-67 value ≥14% (0.907, 0.978, and 0.941 vs. 0.735, 0.778, and 0.761 × 10(-3) mm(2) /s, respectively) (P < 0.01). There was no significant correlation between ADCmedian and tumor size, histologic grade, estrogen receptor expression, and progesterone receptor expression (P = 0.272, 0.113, 0.261, and 0.181, respectively). For most ADC parameters except for ADCmin , the mean of variable ADC parameters of HER2-positive, luminal A, luminal B-HER2(+), triple-negative, and luminal B-HER2(-) diseases were arranged in descending order (1.175, 0.936, 0.863, 0.811, and 0.665 × 10(-3) mm(2) /s in ADCmedian , respectively) with statistical significant difference (P < 0.001). In multivariate analysis, histologic grade, the Ki-67 index, and HER2 expression were statistically significant explanatory prognostic factors for ADCmedian and the Ki-67 index had the most robust effects on ADC parameters (standardized coefficient = -0.317).

CONCLUSION

Various ADC parameters were correlated with prognostic factors and subtype, except for ADCmin . HER2 positivity showed high ADC values and high Ki-67 index revealed low ADC values.

Incidental thyroid lesions detected by FDG-PET/CT: prevalence and risk of thyroid cancer

BACKGROUND

Incidentally found thyroid lesions are frequently detected in patients undergoing FDG-PET/CT. The aim of this study was to investigate the prevalence of incidentally found thyroid lesions in patients undergoing FDG-PET/CT and determine the risk for thyroid cancer.

METHODS

FDG-PET/CT was performed on 3,379 patients for evaluation of suspected or known cancer or cancer screening without any history of thyroid cancer between November 2003 and December 2005. Medical records related to the FDG-PET/CT findings including maximum SUV(SUVmax) and pattern of FDG uptake, US findings, FNA, histopathology received by operation were reviewed retrospectively.

RESULTS

Two hundred eighty five patients (8.4%) were identified to have FDG uptake on FDG-PET/CT. 99 patients with focal or diffuse FDG uptake underwent further evaluation. The cancer risk of incidentally found thyroid lesions on FDG-PET/CT was 23.2% (22/99) and the cancer risks associated with focal and diffuse FDG uptake were 30.9% and 6.4%. There was a significant difference in the SUVmax between the benign and malignant nodules (3.35 +/- 1.69 vs. 6.64 +/- 4.12; P < 0.001). There was a significant correlation between the SUVmax and the size of the cancer.

CONCLUSION

The results of this study suggest that incidentally found thyroid lesions by FDG-PET/CT, especially a focal FDG uptake and a high SUV, have a high risk of thyroid malignancy. Further diagnostic work-up is needed in these cases.

Rapid changes in cytochrome P4502E1 (CYP2E1) activity and other P450 isozymes following ethanol withdrawal in rats

This study describes the effects of chronic ethanol (ETOH) treatment and withdrawal on the rat hepatic mixed-function mono-oxygenase system. Male Sprague-Dawley rats (150-200 g, 10 per group) were administered ETOH as part of the Lieber-deCarli liquid diet for 3 weeks. Ethanol was removed, and the animals were euthanized at 0, 24, 48, 72 and 168 hr post-withdrawal. Microsomes were prepared, and ethanol-inducible cytochrome P4502E1 (CYP2E1) activity was measured using the enzyme markers N-nitrosodimethylamine demethylase (NDMAd), p-nitrophenol hydroxylase (PNPH) and aniline hydroxylase (AH). Activities were found to be induced significantly after chronic ETOH feeding using all three assays (NDMAd, 5-fold; PNPH, 3.5-fold; AH, 9-fold). Upon ETOH withdrawal, all three activities dropped markedly, with NDMAd and PNPH at control values at 24 hr and all subsequent time points. AH activity remained 3-fold higher than controls at 24, 48 and 72 hr. Western blot analyses showed that immunoreactive CYP2E1 returned to control at 24 hr, consonant with NDMAd and PNPH activities. The prolonged induction of AH activity following ETOH withdrawal indicates that it is not a specific marker of CYP2E1-catalyzed reactions. Collectively, these data are suggestive of a rapid mechanism of CYP2E1 degradation in the rat liver. Of the other parameters investigated in this study, total cytochrome P450 content was increased 2.5-fold after ETOH feeding, with levels dropping markedly 24 hr post-withdrawal. NADPH-dependent cytochrome c reductase activity was unchanged throughout the course of the study. CYP1A1, CYP2B1 and CYP3A activities were assessed by the substrate probes ethoxyresorufin O-dealkylase (EROD), pentoxyresorufin O-dealkylase (PROD) and erythromycin N-demethylase (ERNd). EROD and PROD were induced significantly by ETOH administration (2-fold) at 0 hr, with EROD remaining elevated over controls 24 hr post-withdrawal. Quantitative western blot analysis of CYP1A1 and CYP2B1 revealed a pattern of immunostaining generally consistent with but less variable than levels predicted by the respective substrate markers. Both proteins were induced significantly by chronic ethanol administration (CYP1A1, 1.9-fold; CYP2B1, 4-fold). Induction of these P450 isoforms persisted for several days following withdrawal. In contrast, immunoreactive CYP1A2 was found to decrease significantly (by 30-40%) during ethanol withdrawal (24, 48, 72, 168 hr). ERNd activity was induced significantly by chronic ETOH feeding (2.5-fold) and remained so for 24 hr into the withdrawal period (2-fold). Immunoreactive CYP3A1 was also induced significantly following ETOH administration (0 hr) and 24 hr following withdrawal.(ABSTRACT TRUNCATED AT 400 WORDS)

p53 as a specific prognostic factor in triple-negative breast cancer

OBJECTIVE

A recent suggestion is that the predictive value of a single biomarker may rely on the genetic background on the tumor and that different breast cancer subgroups may have different predictive markers of response to chemotherapy. The prognostic value of p53 in the outcome of adjuvant anthracycline-containing chemotherapy was evaluated according to molecular subclasses defined using the expression of estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2.

METHODS

Subjects were patients (n = 135) with invasive ductal carcinoma treated with adjuvant anthracycline-based chemotherapy between 1994 and 2000 in our hospital. Clinico-pathological features were reviewed by retrospective examination of medical records.

RESULTS

Overall survival rate was not independently predictive by p53 status (P = 0.182). However, in triple-negative cases, there was statistically significant survival difference (P = 0.034) and no statistically significant difference (P = 0.783) in non-triple-negative cases by p53 status. In the Cox proportional hazard analysis, p53 was also strongly predictive for relapse-free survival (P = 0.013) and overall survival (P = 0.049) in triple-negative patients.

CONCLUSIONS

p53 status could be a specific prognostic factor in triple-negative breast cancer patients treated by adjuvant anthracycline-based regimen. When p53 is positive in triple-negative breast cancer, we could expect poor survival, prompting aggressive or alternative treatment.

Role of sonographic elastography in the differential diagnosis of axillary lymph nodes in breast cancer

OBJECTIVES

The purpose of this study was to evaluate the diagnostic utility of sonographic elastography in differentiating reactive and metastatic axillary lymph nodes in breast cancer.

METHODS

A total of 64 lymph nodes (reactive, n = 33; metastatic, n = 31) from 62 patients with breast cancer were examined by both B-mode sonography and elastography from April to July 2009. Two experienced radiologists retrospectively assessed B-mode sonograms by the sum of scores for 4 criteria: short diameter, shape, hilum, and cortical thickening. Elastographic images were given scores of 1 to 4 according to the percentage of high-elasticity areas in the lymph nodes. We compared the diagnostic performance of B-mode sonography, elastography, and combined examinations. We also calculated the strain ratio of the lymph node and subcutaneous fat tissue.

RESULTS

The elasticity score for malignant lymph nodes (mean, 3.1) was higher than the score for benign lymph nodes (mean, 2.2; P < .0001). With a cutoff between elasticity scores of 2 and 3, elastography showed 80.7% sensitivity, 66.7% specificity, and 73.4% accuracy. With a cutoff between B-mode sonographic scores of 1 and 2, B-mode sonography showed 74.2% sensitivity and 78.8% specificity. Combined B-mode and elastographic sonography showed higher sensitivity (87.1%) than B-mode sonography alone. With a strain ratio cutoff point of 2.3, sensitivity was 82.8%, and specificity was 56.3%.

CONCLUSIONS

Sonographic elastography may increase the sensitivity of B-mode sonography in the detection of metastatic axillary lymph nodes.

Role and clinical usefulness of elastography in small breast masses

RATIONALE AND OBJECTIVES

The aim of this study was to evaluate and compare the diagnostic performance of elastography, B-mode ultrasound (US), and a combination of elastography and B-mode US for the differentiation of small breast masses.

MATERIALS AND METHODS

A total of 315 breast masses < 1 cm (267 benign, 48 malignant) in 278 patients were examined with B-mode US and elastography. Histopathologic results were used as a reference standard. Two radiologists retrospectively evaluated the B-mode images according to the American College of Radiology Breast Imaging Reporting and Data System and elastographic images according to the elasticity scoring classification system proposed by Itoh et al and the strain ratio. B-mode US and elastography were combined according to the cutoff value. The diagnostic performance of B-mode US, elastography, and the combination of the two modalities was compared using receiver-operating characteristic curve analysis.

RESULTS

The mean elasticity score for malignant masses (3.02 ± 1.33) was significantly higher than that for benign masses (1.72 ± 0.78) (P < .001). Areas under the receiver-operating characteristic curves were 0.616 for B-mode US, 0.784 for elasticity score, 0.668 for strain ratio, 0.727 for the combination of B-mode US and elasticity score, and 0.701 for the combination of B-mode US, elasticity score, and strain ratio. The sensitivity, specificity, positive predictive value, and negative predictive value were 93.8%, 51.7%, 25.9%, and 97.9%, respectively, when elasticity score and B-mode US were combined as follows: downgrade of B-mode US assessment category in cases with elasticity scores of 1, no change in cases with scores of 2 or 3, and upgrade in cases with scores of 4 or 5.

CONCLUSION

Elasticity score alone showed the best diagnostic performance, but a combination of B-mode US and elasticity score may have predictive value for the differentiation of benign and malignant lesions <1 cm.

Diagnostic value of breast MRI for predicting metastatic axillary lymph nodes in breast cancer patients: diffusion-weighted MRI and conventional MRI

PURPOSES

To evaluate the diagnostic value of diffusion-weighted MRI (DWI) and combination of conventional MRI and DWI to predict metastatic axillary lymph nodes in breast cancer.

MATERIALS AND METHODS

Two hundred fifty-two breast cancer patients with 253 axillae were included. The morphological parameters on axial T2-weighted images without fat saturation and apparent diffusion coefficient (ADC) values were retrospectively analyzed. An independent t-test/chi-square test and receiver operating characteristics (ROC) curve analysis were used.

RESULTS

On conventional MRI, short and long axis length, maximal cortical thickness, relative T2 value, loss of fatty hilum (p<0.001 for each), and eccentric cortical thickening (p<0.003) were statistically significantly different between the metastatic and nonmetastatic groups. The short axis to long axis ratio was not a statistically significant parameter. The ADC value was significantly different between the 2 groups, with an AUC that was higher than that of conventional MR parameters (AUC, 0.815; threshold, ≤0.986×10-3 mm(2)/sec; sensitivity, 75.8%; specificity, 83.9%). Using the adopted thresholds for each parameter, a total number of findings suggesting malignancy of 4 or higher was determined as the threshold, with high specificity (90.1%).

CONCLUSION

Using conventional MRI and DWI, we can evaluate the axilla in breast cancer with high specificity.

BCL2 as a Subtype-Specific Prognostic Marker for Breast Cancer

PURPOSE

B-cell lymphoma 2 (BCL2) is an antiapoptosis protein and an important clinical breast cancer prognostic marker. As the role of BCL2 is dependent on the estrogen receptor (ER) status, this effect might differ according to molecular subtypes. The aim of this study was to evaluate the relationship between the prognostic outcomes and BCL2 expression among the molecular subtypes.

METHODS

We retrieved the data of 1,356 patients who were newly diagnosed with malignant breast cancer between November 2006 and November 2011. Immunohistochemistry was used to measure ER, progesterone receptor, human epidermal growth factor receptor 2 (HER2), Ki-67, and BCL2 expression. We classified breast cancer into five molecular subtypes based on the 13th St. Gallen International Expert Consensus, including luminal A, luminal B (HER2-negative), luminal B (HER2-positive), HER2-overexpression, and triple-negative subtypes. We analyzed the clinicopathological features and assessed the correlation between BCL2 expression and clinical outcomes, such as relapse-free survival (RFS) and disease-specific survival (DSS) according to the five molecular subtypes.

RESULTS

A total of 605 cases of breast cancer (53.8%) showed BCL2 expression. BCL2-positive expression was associated with young age (<50 years, p=0.036), lower histological grade (p<0.001), low Ki-67 level (<14%, p<0.001), hormone receptor positivity (p<0.001), HER2 negativity (p<0.001), luminal breast cancer (p<0.001), and low recurrence rate (p=0.016). BCL2-positive expression was also associated with favorable 5-year RFS (p=0.008, 91.4%) and DSS (p=0.036, 95.6%) in all the patients. BCL2-positive expression in luminal A breast cancer resulted in significantly favorable 5-year RFS and DSS (p=0.023 and p=0.041, respectively). However, BCL2 expression was not associated with the prognosis in the other subtypes.

CONCLUSION

The prognostic role of BCL2 expression in breast cancer is subtype-specific. BCL2 expression differs according to the molecular subtype and is a good prognostic marker for only luminal A breast cancer.

Readout-segmented echo-planar imaging in diffusion-weighted mr imaging in breast cancer: comparison with single-shot echo-planar imaging in image quality

Objective

The purpose of this study was to compare the image quality of standard single-shot echo-planar imaging (ss-EPI) and that of readout-segmented EPI (rs-EPI) in patients with breast cancer.

Materials and Methods

Seventy-one patients with 74 breast cancers underwent both ss-EPI and rs-EPI. For qualitative comparison of image quality, three readers independently assessed the two sets of diffusion-weighted (DW) images. To evaluate geometric distortion, a comparison was made between lesion lengths derived from contrast enhanced MR (CE-MR) images and those obtained from the corresponding DW images. For assessment of image parameters, signal-to-noise ratio (SNR), lesion contrast, and contrast-to-noise ratio (CNR) were calculated.

Results

The rs-EPI was superior to ss-EPI in most criteria regarding the qualitative image quality. Anatomical structure distinction, delineation of the lesion, ghosting artifact, and overall image quality were significantly better in rs-EPI. Regarding the geometric distortion, lesion length on ss-EPI was significantly different from that of CE-MR, whereas there were no significant differences between CE-MR and rs-EPI. The rs-EPI was superior to ss-EPI in SNR and CNR.

Conclusion

Readout-segmented EPI is superior to ss-EPI in the aspect of image quality in DW MR imaging of the breast.