So-Youn Jung

Protein and lipid MALDI profiles classify breast cancers according to the intrinsic subtype

BackgroundMatrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) has been demonstrated to be useful for molecular profiling of common solid tumors. Using recently developed MALDI matrices for lipid profiling, we evaluated whether direct tissue MALDI MS analysis on proteins and lipids may classify human breast cancer samples according to the intrinsic subtype.MethodsThirty-four pairs of frozen, resected breast cancer and adjacent normal tissue samples were analyzed using histology-directed, MALDI MS analysis. Sinapinic acid and 2,5-dihydroxybenzoic acid/α-cyano-4-hydroxycinnamic acid were manually deposited on areas of each tissue section enriched in epithelial cells to identify lipid profiles, and mass spectra were acquired using a MALDI-time of flight instrument.ResultsProtein and lipid profiles distinguish cancer from adjacent normal tissue samples with the median prediction accuracy of 94.1%. Luminal, HER2+, and triple-negative tumors demonstrated different protein and lipid profiles, as evidenced by permutation P values less than 0.01 for 0.632+ bootstrap cross-validated misclassification rates with all classifiers tested. Discriminatory proteins and lipids were useful for classifying tumors according to the intrinsic subtype with median prediction accuracies of 80.0-81.3% in random test sets.ConclusionsProtein and lipid profiles accurately distinguish tumor from adjacent normal tissue and classify breast cancers according to the intrinsic subtype.

Phase II Parallel Group Study Showing Comparable Efficacy Between Premenopausal Metastatic Breast Cancer Patients Treated With Letrozole Plus Goserelin and Postmenopausal Patients Treated With Letrozole Alone As First-Line Hormone Therapy

PURPOSE Goserelin and letrozole in premenopausal patients can result in clinical outcomes comparable to those obtained by letrozole alone in postmenopausal patients with metastatic breast cancer (MBC). PATIENTS AND METHODS A total of 73 patients with hormone-responsive MBC were included. Of those, 35 premenopausal patients received goserelin (3.6 mg subcutaneously every 28 days) plus letrozole (2.5 mg orally daily), and 38 postmenopausal patients received letrozole alone as their first-line endocrine therapy in a metastatic setting. RESULTS Baseline characteristics were similar in the two groups, except for a younger age (median, 41 v 53.5 years; P < .001) and a shorter disease-free interval (median, 1.8 v 3.3 years; P = .03) in the premenopausal group. Clinical benefit rates were comparable between the two groups (77% v 74%; P = .77). With the median follow-up of 27.4 months, there was no statistical difference in the median time to progression between the two groups (9.5 months [95% CI, 6.4 to 12.1 months] v 8.9 months [95% CI, 6.4 to 13.3 months]). In patients who did not receive bisphosphonate, letrozole +/- goserelin caused a greater loss of bone mineral density at 6 months compared with that of patients receiving bisphosphonate treatment (premenopausal group, -16.7% v 53.9%; P = .002 and postmenopausal group, -13.3% v 17.4%; P = .04 at the lumbar spine). CONCLUSION Clinical efficacies in premenopausal MBC patients with combined letrozole and goserelin therapy were comparable to those in postmenopausal patients treated with letrozole alone. Although letrozole +/- goserelin resulted in a modest increase in bone resorption, concurrent treatment with bisphosphonate could prevent bone loss at 6 months.

The invasive lobular carcinoma as a prototype luminal A breast cancer: A retrospective cohort study

BackgroundAlthough the invasive lobular carcinoma (ILC) is the second most frequent histologic subtype in Western countries, its incidence is much lower in Asia, and its characteristics are less well known.MethodsWe assessed the clinical characteristics and outcomes of 83 Korean patients (2.8%) with ILC for comparison with 2,833 (97.2%) with the invasive ductal carcinoma (IDC), including 1,088 (37.3%) with the luminal A subtype (LA-IDC).ResultsThe mean age of all patients was 48.2 years, with no significant differences among the groups. Compared to IDC, ILC showed a larger tumor size (≥T2, 59.8% vs. 38.8%, P = 0.001), a lower histologic grade (HG 1/2, 90.4% vs. 64.4%, P < 0.001), more frequent estrogen receptor positive (90.4% vs. 64.4%, P < 0.001), progesterone receptor positive (71.1% vs. 50.1%, P < 0.001) and HER2 negative (97.5% vs. 74.6%, P < 0.001) status, and lower Ki-67 expression (10.3% ± 10.6% vs. 20.6% ± 19.8%, P < 0.001), as well as being more likely to be of the luminal A subtype (91.4% vs. 51.2%, P < 0.001). Six (7.2%) ILC and 359 (12.7%) IDC patients developed disease recurrence, with a median follow-up of 56.4 (range 4.9-136.6) months. The outcome of ILC was close to LA-IDC (HR 0.77 for recurrence, 95% CI 0.31-1.90, P = 0.57; HR 0.75 for death, 95% CI 0.18-3.09, P = 0.70) and significantly better than for the non-LA-IDC (HR 1.69 for recurrence, 95% CI 1.23-2.33, P = 0.001; HR 1.50 for death, 95% CI 0.97-2.33, P = 0.07).ConclusionsILC, a rare histologic type of breast cancer in Korea, has distinctive clinicopathological characteristics similar to those of LA-IDC.

A Model to Estimate the Risk of Breast Cancer-Related Lymphedema: Combinations of Treatment-Related Factors of the Number of Dissected Axillary Nodes, Adjuvant Chemotherapy, and Radiation Therapy

PURPOSE The development of breast cancer-related lymphedema (LE) is closely related to the number of dissected axillary lymph nodes (N-ALNs), chemotherapy, and radiation therapy. In this study, we attempted to estimate the risk of LE based on combinations of these treatment-related factors. METHODS AND MATERIALS A total of 772 patients with breast cancer, who underwent primary surgery with axillary lymph node dissection from 2004 to 2009, were retrospectively analyzed. Adjuvant chemotherapy (ACT) was performed in 677 patients (88%). Among patients who received radiation therapy (n=675), 274 (35%) received supraclavicular radiation therapy (SCRT). RESULTS At a median follow-up of 5.1 years (range, 3.0-8.3 years), 127 patients had developed LE. The overall 5-year cumulative incidence of LE was 17%. Among the 127 affected patients, LE occurred within 2 years after surgery in 97 (76%) and within 3 years in 115 (91%) patients. Multivariate analysis showed that N-ALN (hazard ratio [HR], 2.81; P<.001), ACT (HR, 4.14; P=.048), and SCRT (HR, 3.24; P<.001) were independent risk factors for LE. The total number of risk factors correlated well with the incidence of LE. Patients with no risk or 1 risk factor showed a significantly lower 5-year probability of LE (3%) than patients with 2 (19%) or 3 risk factors (38%) (P<.001). CONCLUSIONS The risk factors associated with LE were N-ALN, ACT, and SCRT. A simple model using combinations of these factors may help clinicians predict the risk of LE.

Locoregional Recurrence of Breast Cancer in Patients Treated With Breast Conservation Surgery and Radiotherapy Following Neoadjuvant Chemotherapy

PURPOSE Breast conservation surgery (BCS) and radiotherapy (RT) following neoadjuvant chemotherapy (NCT) have been linked with high locoregional recurrence (LRR) rates and ipsilateral breast tumor recurrence (IBTR) rates. The purpose of this study was to analyze clinical outcomes in patients who exhibited LRR and IBTR after being treated by BCS and RT following NCT. METHODS AND MATERIALS In total, 251 breast cancer patients treated with BCS and RT following NCT between 2001 and 2006 were included. All patients had been shown to be clinically node-positive. Clinical stage at diagnosis (2003 AJCC) was II in 68% of patients and III in 32% of patients. Of those, 50%, 35%, and 15% of patients received anthracycline-based, taxane-based, and combined anthracycline-taxane NCT, respectively. All patients received RT. RESULTS During follow-up (median, 55 months), 26 (10%) patients had LRR, 19 of these patients had IBTR. Five-year actuarial rates of IBTR-free and LRR-free survival were 91% and 89%, respectively. In multivariate analyses, lack of hormone suppression therapy was found to increase both LRR and IBTR rates. Hazard ratios were 7.99 (p<0.0001) and 4.22 (p=0.004), respectively. Additionally, pathology stage N2 to N3 increased LRR rate (hazard ratio, 4.22; p=0.004), and clinical AJCC stage III IBTR rate (hazard ratio, 9.05; p=0.034). Achievement of pathological complete response and presence of multifocal tumors did not affect LRR or IBTR. CONCLUSIONS In patients with locally advanced disease, who were clinically node-positive at presentation, BCS after NCT resulted in acceptably low rates of IBTR and LRR. Mastectomy should be considered as an option in patients who present with clinical stage III tumors or who are not treated with adjuvant hormone suppression therapy, because they exhibit high IBTR rates after NCT and BCS.

Methylation patterns of genes coding for drug-metabolizing enzymes in tamoxifen-resistant breast cancer tissues.

The biological mechanisms underlying resistance to tamoxifen are of considerable clinical significance. However, little is known about the correlation between tamoxifen resistance and methylation of genes related to drug-metabolizing enzymes. To address this issue, we examined the methylation pattern and expression of the selected genes coding for drug-metabolizing enzymes, including COMT, CYP1A1, CYP2D6, NAT1, and SULT1A1 in tamoxifen-resistant and control breast cancers. Bisulfite genomic sequencing and methylation-specific PCR were carried out to evaluate the methylation patterns of the five genes from control (n = 74) and tamoxifen-resistant tissues (n = 37) chosen by an age-matched sampling method. Also, end-point reverse transcriptase polymerase chain reaction (RT-PCR) and real-time RT-PCR were performed to determine RNA expression of the genes. Bisulfite genomic sequencing revealed methylation of the NAT1 gene in 25 of the control cancers (33.8%) and 23 of the resistant tumors (62.2%). Of the five genes, only NAT1 showed a significant lower methylation rate in the control group than in the resistant group (p = 0.004). No significant difference of the methylation rate was found in the other four genes including COMT, CYP1A1, CYP2D6, and SULT1A1 (p > 0.05). Furthermore, the expression rate of NAT1 mRNA was lower in the tumors from the resistant group than in control tumors (28.6% vs. 65.2%, p = 0.031). Real-time RT-PCR analysis demonstrated that the NAT1 gene was more down-regulated in resistant tissues than in control group (p = 0.023). Moreover, malignant cells from the resistant cases demonstrated a higher percentage of positive staining for Ki67 (p = 0.001) and cyclin D1 (p = 0.043) than those from the control group. Taken together, the higher methylation rate of the NAT1 gene is related to tamoxifen resistance, and this fact supports the hypothesis that hypermethylation of the NAT1 gene might affect the initiation of tamoxifen resistance.

Oncological safety and quality of life associated with mastectomy and immediate breast reconstruction with a latissimus dorsi myocutaneous flap.

Abstract:  To determine the quality of life (QoL) of breast cancer patients who underwent mastectomy and immediate breast reconstruction with a latissimus dorsi myocutaneous flap (LD), and the oncological safety of the procedure. Between May 2001 and March 2007, 2,566 patients had breast cancer surgery at the National Cancer Center, Korea. Of the 2,566 patients, 1,699 had breast‐conserving surgery (BCS) and 120 had a mastectomy with an immediate LD. We retrospectively compared the oncologic safety of the two techniques. We also assessed the QoL using the EORTC QLQ BR‐23 and Zung’s self‐rating depression scale in 52 LD patients, 104 age‐ and stage‐matched patients who underwent BCS, and 104 age‐matched healthy women. The LD group had earlier stage disease than the BCS group at baseline, but following surgery, the groups did not differ in the rates of local recurrence or systemic metastases. Compared with the healthy group, the patient groups had poorer functioning and more depression (p < 0.001). Among the patient groups, the LD group reported lower scores for body image (p = 0.007) and future perspective (p = 0.023) than the BCS group. In the LD group, patients who received neoadjuvant chemotherapy reported lower scores for future perspective and higher scores for depression than those who did not receive neoadjuvant chemotherapy (p < 0.001). The BCS and LD groups did not differ in oncological outcome, and the QoL of patients in the LD group was not always good. Mastectomy with immediate reconstruction should be considered carefully and tailored to the patient’s needs and characteristics.

Fibrin Glue Reduces the Duration of Lymphatic Drainage after Lumpectomy and Level II or III Axillary Lymph Node Dissection for Breast Cancer: A Prospective Randomized Trial

This randomized prospective study investigated the effect of fibrin glue use on drainage duration and overall drain output after lumpectomy and axillary dissection in breast cancer patients. A total of 100 patients undergoing breast lumpectomy and axillary dissection were randomized to a fibrin glue group (N=50; glue sprayed onto the axillary dissection site) or a control group (N=50). Outcome measures were drainage duration, overall drain output, and incidence of seroma. Overall, the fibrin glue and control groups were similar in terms of drainage duration, overall drain output, and incidence of seroma. However, subgroup analysis showed that fibrin glue use resulted in a shorter drainage duration (3.5 vs. 4.7 days; p=0.0006) and overall drain output (196 vs. 278 mL; p=0.0255) in patients undergoing level II or III axillary dissection. Fibrin glue use reduced drainage duration and overall drain output in breast cancer patients undergoing a lumpectomy and level II or III axillary dissection.

Hypomethylation of the interleukin-10 gene in breast cancer tissues

The purpose of the study was to evaluate the methylation status of the interleukin-10 (IL-10) gene in breast cancer tissues compared with normal and benign breast disease tissues. Between 2000 and 2001, we used paraffin-embedded specimens of 30 normal, 31 benign and 72 breast cancer tissues from the National Cancer Center, Korea. The methylation patterns of the IL-10 gene were evaluated using bisulfite DNA sequencing and the expression levels of IL-10 mRNA were evaluated using real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) and reverse transcriptase-polymerase chain reaction (RT-PCR). The methylation rates of the IL-10 gene were significantly lower in malignant tumors than in benign and normal tissues (normal; 63.3%, benign; 74.2%, cancer; 45.8%, p = 0.02). The methylation density rates of the IL-10 gene were also significantly lower in malignant tumors (normal; 59.68 ± 7.12%, benign; 48.89 ± 7.45%, cancer; 30.56 ± 4.18%, p = 0.001). Tissues with aberrant methylation of the IL-10 gene showed significantly lower rates of mRNA expression compared with unmethylated cases (12.5% vs. 68.0%, p = 0.012). The mRNA expression of tissues with unmethylated IL-10 was upregulated approximately ten thousand-fold compared to those with IL-10 methylation in the real-time RT-PCR experiment. IL-10 methylation demonstrated a significant association with lower expression of Ki-67 (9.36 ± 2.43 vs. 19.68 ± 3.42, p = 0.02). IL-10 methylation in cancer tissues is lower than that in normal and benign breast tissues, and DNA hypomethylation in the gene influences gene activation. Our data suggest that hypomethylation of the IL-10 gene can be involved in the process of breast carcinogenesis.

Identification of Prognostic Risk Factors for Transient and Persistent Lymphedema after Multimodal Treatment for Breast Cancer

Purpose The purpose of this study is to identify risk factors for transient lymphedema (TLE) and persistent lymphedema (PLE) following treatment for breast cancer. Materials and Methods A total of 1,073 patients who underwent curative breast surgery were analyzed. TLE was defined as one episode of arm swelling that had resolved spontaneously by the next follow-up; arm swelling that persisted over two consecutive examinations was considered PLE. Results At a median follow-up period of 5.1 years, 370 cases of lymphedema were reported, including 120 TLE (11.2%) and 250 PLE (23.3%). Initial grade 1 swelling was observed in 351 patients, of which 120 were limited to TLE (34%), while the other 231 progressed to PLE (66%). All initial swelling observed in TLE patients was classified as grade 1. In multivariate analysis, chemotherapy with taxane and supraclavicular radiation therapy (SCRT) were associated with development of TLE, whereas SCRT, stage III cancer and chemotherapy with taxane were identified as risk factors for PLE (p < 0.05). The estimated incidence of TLE among initial grade 1 patients was calculated using up to three treatment-related risk factors (number of dissected axillary lymph nodes, SCRT, and taxane chemotherapy). The approximate ratios of TLE and PLE based on the number of risk factors were 7:1 (no factor), 1:1 (one factor), 1:2 (two factors), and 1:3 (three factors). Conclusion One-third of initial swelling events were transient, whereas the other two-thirds of patients experienced PLE. Estimation of TLE and PLE based on known treatment factors could facilitate prediction of this life-long complication.