Investigation of recurrence prediction ability of EndoPredict® using microarray data from fresh frozen tissues in ER-positive, HER2-negative breast cancer and indication expansion of EndoPredict® from microarray data from fresh-frozen to FFPE tissues

BACKGROUND

EndoPredict® (EP) is a multigene assay to predict distant recurrence risk in luminal breast cancer. EP measures the expression of 12 genes in primary tumor by qRT-PCR from formalin-fixed paraffin-embedded (FFPE) tissues and calculates EP risk score that indicates the risk of distant recurrence. We evaluated the performance of EP in predicting distant recurrence risk using microarray data from fresh frozen (FF) tissues. We also examined the applicability of EP to microarray data from FFPE tissues.

METHODS

We analyzed the publicly available data of 431 node-negative and 270 node-positive patients with luminal breast cancer who received endocrine therapy alone. We evaluated the prognostic value of EP using microarray data from FF tissues. Next, we created an algorithm to calculate EP risk score using microarray data from FFPE tissues. We examined the correlation coefficient of EP risk score and concordance rate of EP risk high/low using microarray data from FFPE/FF tissue pairs in a validation set of 39 patients.

RESULTS

In 431 node-negative patients, the distant recurrence-free survival (DRFS) rate was significantly worse in those with high EP risk scores (P = 3.68 × 10-6, log-rank). The 5-year DRFS was 95.2% in those with low EP risk score. In the validation set, the correlation coefficient of EP risk score was 0.93 and the concordance rate of EP risk high/low was 91.7%.

CONCLUSIONS

EP using microarray data from FF tissues was useful in predicting distant recurrence risk in luminal breast cancer, and EP might be utilized in microarray data from FFPE tissues.

Seven-plus hours of daily sedentary time and the subsequent risk of breast cancer: Japan Multi-Institutional Collaborative Cohort Study

This study aimed to investigate the association between daily sedentary time and the risk of breast cancer (BC) in a large Japanese population. The participants were 36,023 women aged 35-69 years from the Japan Multi-Institutional Collaborative Cohort Study. Cox proportional hazards analysis was used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for BC incidence in relation to time spent sedentarily (categorical variables: <7 and ≥7 hours/day [h/d]). Additionally, the associations of BC incidence to the joint effect of sedentary time with each component of physical activity, such as leisure-time metabolic equivalents (METs), frequency of leisure-time physical activity, and daily walking time, were examined. During 315,189 person-years of follow-up, 554 incident cases of BC were identified. When compared to participants who spent <7 h/d sedentary, those who spent ≥7 h/d sedentary have a significantly higher risk of BC (HR, 1.36; 95% CI, 1.07-1.71). The corresponding HRs among participants who spent ≥7 h/d sedentary with more physical activity, such as ≥1 h/d for leisure-time METs, ≥3 days/week of leisure-time physical activity, and ≥1 h/d of daily walking were 1.58 (95% CI, 1.11-2.25), 1.77 (95% CI, 1.20-2.61), and 1.42 (95% CI, 1.10-1.83), respectively, compared with those who spent <7 h/d sedentary. This study found that spending ≥7 h/d of sedentary time is associated with the risk of BC. Neither leisure-time physical activity nor walking had a BC-preventive effect in those with ≥7 h/d of sedentary time.

The Feasibility of Omitting Postoperative Radiotherapy in Japanese Patients With Ductal Carcinoma In Situ of Breast Treated With Breast-Conserving Surgery

Background To analyze the feasibility of omitting postoperative radiotherapy (PORT) after breast-conserving surgery (BCS) in Japanese patients with ductal carcinoma in situ (DCIS). Materials and methods We retrospectively analyzed 88 patients with small pure DCIS (median diameter 1.1 cm, ≤ 4 cm) who underwent BCS with (n = 39) or without (n = 49) PORT. The primary and secondary endpoints were ipsilateral breast tumor recurrence (IBTR) and overall survival (OS), respectively, between the groups that received PORT and those that did not. Results The PORT group included a high number of margin-positive cases. The incidence of IBTR was 2.4% (95% confidence interval (CI), 0.3-15.7%) and 2.8% (95% CI, 0.4-18.2%) at five years and 5.5% (95% CI, 1.4-20.6%) and 2.8% (95% CI, 0.4-18.2%) at 10 years in patients without and with PORT, respectively (p = 0.686). In the margin-negative group, only one patient showed IBTR without RT (2.3%), whereas no patient with PORT experienced IBTR (0%). To date, there have been no regional or distant metastases; therefore, no patient has experienced breast cancer-related deaths. The OS rates were 97.7% (95% CI, 84.9-99.6%) and 100% at 10 years in patients without and with PORT, respectively (p = 0.372). Conclusion This study suggests that the omission of PORT after BCS could be a feasible option for selected Japanese patients but requires further investigation to identify the low-risk factor in patients who can omit PORT.

Optimal Treatment of Hormone Receptor-positive Advanced Breast Cancer Patients With Palbociclib

BACKGROUND/AIM

Palbociclib was the first cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor approved worldwide. Currently, CDK4/6 inhibitors are strongly recommended for endocrine therapy in the first or second line with hormone receptor-positive advanced breast cancer. It is expected the use of CDK4/6 inhibitor will further increase. Therefore, the aim was to investigate and better understand the use of palbociclib.

PATIENTS AND METHODS

We retrospectively analyzed the data of patients with advanced breast cancer who were treated with palbociclib in three hospitals between 2018 and 2022. Clinical data were obtained from the patients' medical electronic records.

RESULTS

A total of 143 patients were enrolled. The median age was 66 years (range=33-89), and the majority (90.9%) were postmenopausal patients. In total, median time-to-treatment discontinuation (TTD) (95% confidence interval, CI) was 7 (6-10) months. Median TTD (95% CI) was 13 (7-20) months for the first or second line, and significantly prolonged compared to TTD for the third or later lines with palbociclib (p<0.0001). The importance of front-line use was indicated. Multivariate analyses showed that no visceral metastasis or first or second line therapy influenced the longer TTD. Between patients above or below 70 years of age, older age did not negatively affect TTD, though there were significantly more cases of dose reduction or withdrawal in patients over 70 years old. The variation of adverse events (AEs) among hospitals was very large (9.0%, 31.3%, 4.5%). We found that understanding of AE management was important.

CONCLUSION

This study showed that dose reduction or withdrawal of palbociclib had no harmful effects in Japanese patients. Efficacy was also high in older patients. It is important to manage palbociclib administration more safely and appropriately. A combination of dose reduction and withdrawal is key to this therapeutic strategy.

Multi-gene assay 95- and 155-gene classifiers for prognosis prediction and chemotherapy omission in lymphnode positive luminal-type breast cancer

BACKGROUND

The prognosis of lymphnode positive breast cancer is worse than that of lymph node negative breast cancer but some cases may not require chemotherapy. We investigated the ability of the new multi-gene assays, 95GC and 155GC, to identify patients with lymphnode positive Luminal-type breast cancer whose chemotherapy can be omitted relatively safely.

PATIENTS AND METHODS

We extracted 1721 cases of lymphnode positive Luminal-type breast cancer from 22 public database Caucasoid cohorts and 3 Asian cohorts, and performed recurrence prognosis analysis with 95GC and 155GC.

RESULTS

Using 95GC, the cases were stratified as the high (n = 917) and low (n = 202) groups according to the prognosis of lymphnode positive Luminal-type endocrine only breast cancer. The 5 years DRFS in the low risk group was relatively good at 90%, and no additional effect of chemotherapy was observed, suggesting omission of chemotherapy. The recurrence prognosis was also significantly dichotomized into the high and low risks by 95GC in 21GC RS 0-25 cases. Here, we found a group with poor prognosis even in post-menopause RS 0-25 and requiring chemotherapy. Additionally, a group in which the prognosis was good in pre-menopause RS 0-25, and the omission of chemotherapy could be considered. Patients in the high-risk group at 155GC had poor prognosis after chemotherapy. 155GC also showed a group that chemotherapy alone was not sufficient.

CONCLUSION

In this study, we demonstrated the possibility of accurately selecting patient groups for which chemotherapy can be omitted from lymphnode positive Luminal-type breast cancer.

Validation of the prognosis of patients with ER‑positive, HER2‑negative and node‑negative invasive breast cancer classified as low risk by Curebest™ 95GC Breast in a multi‑institutional registry study

Curebest™ 95GC breast (95GC) is a multigene classifier we developed for the prognostic prediction of patients with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative and node-negative (ER+/HER2-/n0) invasive breast cancer treated with adjuvant endocrine therapy alone. The aim of the preset study was to evaluate the clinical utility of 95GC in a multiinstitutional registry study. Patients (n=215) with ER⁺/HER2^-/n0 invasive breast cancer who had undergone the 95GC assay in seven hospitals were consecutively recruited in the registry study at various postoperative times. At recruitment, no patients had disease recurrences and were prospectively followed up for a median of 62 (range, 6-91) postoperative months. Of the 124 patients classified as 95GC low risk, 118 received adjuvant endocrine therapy alone and six received adjuvant chemo-endocrine therapy. Only two patients developed distant recurrences, and the 5-year distant recurrence-free survival (DRFS) was as high as 98.0%. Of the 91 patients classified as 95GC high risk, 81 received adjuvant chemo-endocrine therapy and 10 received adjuvant endocrine therapy alone. A total of four of these patients developed distant recurrences (5-year DRFS=95.5%). Among the 95GC high-risk patients, prognosis was significantly improved for the 81 treated with adjuvant chemo-endocrine therapy compared with for the 77 (historical controls) treated with adjuvant endocrine therapy alone (P=0.0002; hazard ratio, 0.24). Compared with the St. Gallen 2013 guideline, a significant de-escalation from 73.1% (155/212) to 40.6% (86/212) in adjuvant chemotherapy was achieved. The excellent prognosis of patients with ER⁺/HER2^-/n0 invasive breast cancer classified as 95GC low risk could be validated in the present registry study, indicating that 95GC is useful for safe de-escalation of adjuvant chemotherapy in patients with ER⁺/HER2^-/n0 invasive breast cancer.

Observational study of axilla treatment for breast cancer patients with 1 to 3 positive micrometastases or macrometastases in sentinel lymph nodes

e12576

Background: From the results of ACOSOG Z0011, IBCSG23-01 and AMAROS trials, axilla surgery in node-positive breast cancer (BC) tends to be less invasive with sentinel node biopsy (SNB) followed by adjuvant therapy and regional node irradiation (RNI). However, optimized axilla treatment including SNB without RNI is still debated. The Japanese Society for Sentinel Node Navigation Surgery conducted a multi-institutional prospective cohort study to compare SNB with SNB followed by axillary lymph node dissection (ALND) in cases with positive-sentinel lymph nodes (SLN)(UMIN No. 000011782, Jpn J Clin Oncol, p.876-9, 2014). Methods: Female BC patients with cT1-3N0-1M0 were eligible. When 1 to 3 positive micrometastases or macrometastases in SLN were confirmed by histological or molecular diagnosis, SNB alone or additional ALND had been decided by physician’s discretion. Primary chemotherapy before or after SNB was acceptable for registration. Lymph node sampling was also allowed in the SNB group. Cases with bilateral BC, isolated tumor cells only in SLN, past history of invasive cancer within 5 years at the registration were ineligible. The primary endpoint was the 5-year recurrence rate of regional node (RN) in the SNB group. The secondary endpoint was overall survival (OS). We planned to collect 240 patients to reject that the 5-year recurrence rate of RN was more than 10% assuming the rate 5%. To compare the SNB group and ALND group, the propensity score matching (PSM) was performed. Matching variables were initial treatment, metastatic size and numbers of SLN, clinical stage, age, body mass index, menopausal status, family history, past history of invasive cancer, breast surgery. Results: Eight-hundred eighty cases had been registered between 2013 and 2016. In the 871 eligible cases, 308 cases were the SNB group. At the median follow-up of 6.3 years, 5-year recurrence rate of RN was 2.7% [95% confidence interval, 1.4% to 5.4%] and 5-year OS was 97.6% [94.9% to 98.8%]. After PSM, 209 cases were matched in the SNB and ALND group. Among them, 343 cases (82%) received operation at initial treatment. Partial and total mastectomy was performed in 225 (54%) and 193 cases (46%), respectively. One-positive SLN was recorded in 366 cases (88%), 2 in 48 (11%) and 3 in 4 (1%). Macrometastases and micrometastases in SLN were diagnosed in 271 (65%) and 147 cases (35%), respectively. Three-hundred seventy-six cases (90%) belonged to luminal-like subtype. RNI was underwent in 42 cases (20%) of the SNB group and 13 cases (6%) of the ALND group. Five-year recurrence rate of RN was 2.1% [0.8% to 5.5%] and 2.0% [0.8% to 5.3%] for the SNB and ALND group, respectively. Conclusions: Our series suggests that RNI is not necessary for regional control in cases with 1 to 3 positive SLN. In conclusion, SNB alone is acceptable in cases with fewer metastatic SLN. Clinical trial information: UMIN No. 000011782.

A case of sternal osteomyelitis during treatment with everolimus for recurrent breast cancer

Background

Everolimus is a mechanistic-target-of-rapamycin (mTOR) inhibitor bearing a potent antitumor effect against hormone receptor-positive breast cancer. Here, we report the case of a patient with recurrent breast cancer who developed osteomyelitis during the treatment with everolimus plus exemestane.

Case presentation

A 56-year-old woman with early-stage breast cancer underwent right mastectomy and axillary lymph node dissection at the age of 45. Four years after the surgery, she experienced relapse at the chest wall. Radiotherapy was performed on the chest wall, including the sternum, and denosumab was administered. After several regimens of hormonal therapies, everolimus in combination with exemestane was administered. Three months later, the patient visited our clinic because of continuous fever. A computed tomography scan showed an osteolytic change in the sternal bone with pneumomediastinum, which indicated sternal osteomyelitis. Extensive debridement followed by secondary reconstruction of the chest wall was successfully performed.

Conclusions

Everolimus may cause osteomyelitis of the affected bone as a result of tumor necrosis. Everolimus-induced osteomyelitis may be manageable by extensive debridement performed without delay.

Comparison of the multigene panel test and OncoScan™ for the determination of HER2 amplification in breast cancer

The diagnostic accuracy of the multigene panel test (MPT) and OncoScan™ in the determination of HER2 amplification in breast tumors remains controversial. In the present study, HER2 copy number was analyzed using both MPT and OncoScan™ in 45 breast tumors and was compared with that in fluorescent in situ hybridization (FISH) analysis. Tumors with low cellularity were examined using tumor cell enrichment and fluorescence‑activated cell sorting. Both MPT and OncoScan™ exhibited significant correlations with FISH with respect to the determination of HER2 amplification in breast tumors. However, the correlation coefficient was significantly higher for the comparison of MPT and FISH (r=0.770) compared with that between OncoScan™ and FISH (r=0.564). The accuracy of MPT (93.3%) was slightly higher compared with that in OncoScan™ (84.4%) in determining the HER2 status, which was mostly explained by the higher sensitivity of MPT in tumors with low cellularity (83.3 vs. 33.3%), but not in those with high cellularity (81.8 vs. 72.7%). The specificity was 100% for both tests. The MPT exhibited higher sensitivity in the determination of the amplification of other genes, including MYC, fibroblast growth factor receptor 1 and GATA binding protein 3 in tumors with low cellularity compared with that in tumors with high cellularity. OncoScan™ exhibited low sensitivity without tumor cell enrichment. The results suggested that MPT could be a promising method to determine HER2 status in breast tumors and that it could exhibit improved accuracy compared with that in OncoScan™ in tumors with low cellularity.

A 95-gene signature stratifies recurrence risk of invasive disease in ER-positive, HER2-negative, node-negative breast cancer with intermediate 21-gene signature recurrence scores

PURPOSE

A subset of patients with intermediate 21-gene signature assay recurrence score may benefit from adjuvant chemoendocrine therapy, but a predictive strategy is needed to identify such patients. The 95-gene signature assay was tested to stratify patients with intermediate RS into high (95GC-H) and low (95GC-L) groups that were associated with invasive recurrence risk.

METHODS

Patients with ER-positive, HER2-negative, node-negative breast cancer and RS 11-25 who underwent definitive surgery and adjuvant endocrine therapy without any cytotoxic agents were included. RNA was extracted from archived formalin-fixed, paraffin-embedded samples, and 95-gene signature was calculated.

RESULTS

206 patients had RS of 11-25 (95GC-L, N = 163; 95GC-H, N = 43). In Cox proportional hazards model, 95GC-H was significantly associated with shorter time to recurrence than was 95GC-L (HR 5.94; 95%CI 1.81-19.53; P = 0.005). The correlation between 95-gene signature and 21-gene signature assay scores was not strong (correlation coefficient r = 0.27), which might suggest that 95-gene signature reflects biological characteristics differing from what 21-gene signature shows.

CONCLUSIONS

The 95-gene signature stratifies patients with ER-positive, HER2-negative, node-negative invasive breast cancer and intermediate RS of 11-25 into high and low groups that are associated with recurrence risk of invasive disease. Further retrospective analysis in the prospectively accrued TAILORx population is warranted to confirm that 95-gene signature can identify patients who would benefit from adjuvant chemoendocrine therapy.

Aesthetic utility of addition of nipple-areola recentralization to rotation flap according to nipple tumor distance for patients with lower-outer or upper-inner located breast cancers

We aimed to validate the cosmetic utility of addition of nipple-areola recentralization (NAR) to rotation flap according to nipple tumor distance (NTD) as a volume displacement technique after breast conserving surgery (BCS) for lower-outer and upper-inner breast cancers. Twenty breast cancer patients who had been treated with rotation flap with (Group 1; n = 6) or without (Group 2; n = 14) NAR after BCS for lower-outer or upper-inner located tumors, and those who had undergone BCS without oncoplastic surgical technique for tumors in the same area (Control group; n = 43), were retrospectively investigated. Cosmetic outcome was evaluated using Harvard scale and/or BCCT.core. As a result, the ratio of patients categorized as excellent/good was 83% in Group 1 and 93% in Group 2, respectively, and there was no significant difference between them (P = 0.521). In addition, Group 1 + 2 showed a significantly higher ratio of patients classified as excellent/good than the control group (90% vs. 56%; P = 0.009). After adjustment of clinical background parameters using propensity score matching analysis between Group 1 + 2 and the control group, 12 pairs with similar background factors were matched. Among them, Group 1 + 2 showed a higher ratio of patients categorized as excellent/good than the control group (92% vs. 42%; P = 0.034). In conclusion, addition of NAR to rotation technique according to NTD may enable us to perform a volume displacement after BCS for lower-outer or upper-inner located tumors irrespective of NTD without sacrificing postoperative breast appearance.

Prediction of pathological complete response after neoadjuvant chemotherapy in breast cancer: comparison of diagnostic performances of dedicated breast PET, whole-body PET, and dynamic contrast-enhanced MRI

PURPOSE

To compare the diagnostic performance of ring-type dedicated breast PET (dbPET), whole-body PET (WBPET), and DCE-MRI for predicting pathological complete response (pCR) after neoadjuvant chemotherapy (NAC).

METHODS

This prospective study included 29 women with histologically proven breast cancer on needle biopsy between July 2016 and July 2019 (age: mean 55 years; range 35-78). Patients underwent WBPET followed by ring-type dbPET and DCE-MRI pre- and post-NAC for preoperative evaluation. pCR was defined as an invasive tumor that disappeared in the breast. Standardized uptake values corrected for lean body mass (SULpeak) were calculated for dbPET and WBPET scans. Maximum tumor length was measured in DCE-MRI images. Reduction rates were calculated for quantitative evaluation. Two radiologists independently evaluated the qualitative findings. Reduction rates and qualitative findings were compared between the pCR (n = 7) and non-pCR (n = 22) groups for each modality. Differences in quantitative and qualitative data between the two groups were analyzed statistically.

RESULTS

Significant differences were observed in the reduction rates of dbPET and DCE-MRI (P = 0.01 and 0.03, respectively) between the two groups. Univariate and multiple logistic regression analyses revealed that SULpeak reduction rates in WBPET and dbPET (P = 0.02 and P = 0.01, respectively) and in dbPET (odds ratio, 16.00; 95% CI 1.57-162.10; P = 0.01) were significant indicators associated with pCR, respectively. No between-group differences were observed in qualitative findings in the three modalities.

CONCLUSION

SULpeak reduction rate of dbPET > 82% was an independent indicator associated with pCR after NAC in breast cancer.

The multigene classifiers 95GC/42GC/155GC for precision medicine in ER-positive HER2-negative early breast cancer

In clinical decision‐making, to decide the indication for adjuvant chemotherapy for estrogen receptor‐positive (ER+), human epidermal growth factor receptor‐2‐negative (HER2−), and node‐negative (n0) breast cancer patients, the accurate estimation of recurrence risk is essential. Unfortunately, conventional prognostic factors, such as tumor size, histological grade and ER, progesterone receptor (PR), and HER2 status as well as Ki67 index, are not sufficiently accurate for such estimation. Therefore, several multigene assays (MGAs) based on the mRNA expression analysis of multiple genes in tumor tissue have been developed to better predict patient prognosis. These assays include Oncotype DX, MammaPrint, PAM50, GGI, EndoPredict, and BCI. We developed Curebest™ 95‐Gene Classifier Breast (95GC) classifier, which is unique in that mRNA expression data of all 20 000 human genes are secondarily obtainable, as the 95GC assay is performed using Affymetrix microarray. This can capture mRNA expression of not only 95 genes but also every gene at once, and such gene expression data can be utilized by the other MGAs that we have developed, such as the 155GC, which is used for the prognostic prediction of ER+/HER2− breast cancer patients treated with neoadjuvant chemotherapy. We also developed the 42GC for predicting late recurrence in ER+/HER2− breast cancer patients. In this mini‐review, our recent attempt at the development of various MGAs, which is expected to facilitate the implementation of precision medicine in ER+/HER2− breast cancer patients, is presented with a special emphasis on 95GC.

Impact of tumor cellularity on the HER2 amplification assay by OncoScan™ in breast cancer

HER2 amplification is seen in 20-25% of primary breast cancer cases, and HER2 detection is performed routinely in primary operable, as well as metastatic breast cancer patients. Currently, HER2 is the only gene of which amplification is routinely assayed by fluorescent in situ hybridization (FISH) and/or immunohistochemistry (IHC). However, histochemical assay (FISH/IHC) of multiple target genes is laborious and time-consuming, and simultaneous amplification by microarray is preferred. OncoScan™ is a microarray-based assay capable of whole-genome copy number analysis using DNA extracted from formalin-fixed paraffin-embedded (FFPE) tissues. In the current study, we aimed to investigate the impact of tumor cellularity on the accuracy of OncoScan™ in the determination of HER2 amplification. Our results demonstrated that HER2 amplification by OncoScan™ is accurate, and has a high concordance rate of 93.3% with FISH. However, the concordance rate is poor (66.7%) in cases with a tumor cellularity < 20%. Nevertheless, the addition of FISH to breast tumors with a tumor cellularity < 20% and a HER2 copy number of 4 appears to be useful to minimize false-negative results by OncoScan™.

Determining homologous recombination deficiency scores with whole exome sequencing and their association with responses to neoadjuvant chemotherapy in breast cancer

Recent studies demonstrated that homologous repair deficiency (HRD) score is a useful marker for response to poly (ADP-ribose) polymerase inhibitors or platinum-based chemotherapy. We determined HRD scores and elucidated the clinicopathologic characteristics of HRD-high tumors and their response to non-platinum-based chemotherapy. Primary breast cancer patients (n = 120) were pre-operatively treated with paclitaxel followed by 5-fluorouracil/epirubicin/cyclophosphamide (P-FEC). Germline and somatic homologous recombination related gene mutations (gHRRm and sHRRm, respectively) and HRD scores were analyzed using whole exome sequencing (WES) in tumor tissues obtained before chemotherapy. Of 120 tumors, 30 were determined to be HRD-high tumors, significantly associated with high Ki-67 (P = 0.014), ER negativity (P = 0.007), and PR negativity (P = 0.021). Triple-negative cancers showed significantly higher HRD scores than the luminal, luminal-HER2, and HER2 subtypes (P = 0.023, 0.016, and 0.033, respectively). HRD scores were significantly higher in tumors with gHRRm than in those with sHRRm (P = 0.002) or wild-type HRR genes (P = 1.44e-4), but no significant difference was found in HRD scores between tumors with sHRRm and wild-type HRR genes (P = 0.206). HRD-high tumors had significantly (P = 0.003) higher pCR rates and higher near-pCR rates (P = 0.049) compared with those of the HRD-low tumors in all tumors and the luminal subtype, respectively. HRD-high tumors were associated with aggressive phenotypes and gHRRm, but not sHRRm. Our findings suggested that HRD scores might be useful in predicting response to P-FEC in the luminal subtype.

Enhanced humoral immunity in breast cancer patients with high serum concentration of anti-HER2 autoantibody

Humoral immunity plays a substantial role in the suppression of breast cancer. We have revealed that a high serum concentration of anti‐HER2 autoantibody (HER2‐AAb) is associated with favorable outcomes in patients with invasive breast cancer. Thus, we aimed to clarify the association between high serum concentration of HER2‐AAb and humoral immune response in the tumor microenvironment. Out of 500 consecutive patients with invasive breast cancer, we selected those whose HER2‐AAb values were high (n = 33) or low (n = 20) based on the distribution of HER2‐AAb values of 100 healthy individuals. Tumor and regional lymph node formalin‐fixed paraffin‐embedded samples prepared from the surgical specimens were subjected to immunohistochemistry. We confirmed that the recurrence‐free survival of the high HER2‐AAb group was significantly longer than that of the low HER2‐AAb group (p = 0.015). The numbers of tumor‐infiltrating CD20+ immune cells (ICs) (p < 0.001), IGKC+ICs (p = 0.023), and CXCL13+ ICs (p = 0.044) were significantly higher in the high HER2‐AAb group than in the low HER2‐AAb group. The number of CD4+ ICs in the B‐cell follicles of the regional lymph nodes was also significantly greater in the high HER2‐AAb group than in the low HER2‐AAb group (p = 0.026). Our findings indicate that a high level of HER2‐AAb is associated with enhanced humoral immunity against breast cancer and thus may provide a rationale for the association of HER2‐AAb with favorable prognosis.

Sentinel lymph node biopsy after introducing Twirl® breast markers into suspicious lymph nodes in breast cancer patients

Ten stage I/II breast cancer patients with one or two suspicious lymph nodes (LNs) detected on ultrasonography underwent sentinel LN biopsy (SLNB) after the introduction of Twirl® breast markers into each suspicious LN revealed that each Twirl®-marked LN was SLN and was likely the first SLN. Three patients had less than three SLN metastases and were candidates for sparing completion axillary lymph node dissection (cALND). Indeed, of them, one underwent breast-conserving surgery without cALND and the other two underwent total mastectomy with cALND. These results suggest that, as all suspicious LNs are SLNs, patients can be treated with SLNB alone if they fulfill the ACOSOG Z-0011 criteria, despite suspicious LNs yielding positive results on preoperative fine-needle aspiration cytology.

Effect of Computer-aided Detection System Use on the Duration of MRI-guided Biopsy of the Breast

BACKGROUND/AIM

Magnetic resonance imaging (MRI)-guided breast biopsy is a complex and time-consuming procedure. This study aimed to clarify the factors that affect the duration of the procedure.

PATIENTS AND METHODS

Twenty-eight examinations performed at our institute for 27 lesions detected solely on MRI were analyzed. The correlations between the clinicopathological factors and duration of the procedure were estimated.

RESULTS

The needle guidance method was the only factor that significantly affected the duration of the MRI-guided vacuum-assisted breast biopsy (VAB) (p=0.012). The use of a computer-aided detection (CAD) system with grid breast compression plates had significantly shorter durations (62±12 min) than the manual calculation of coordinates with pillar-type compression plates (76±13 min).

CONCLUSION

This preliminary study showed that the use of a CAD system might shorten the duration of MRI-guided VAB.

Abstract 1604: Association of autoantibodies to HER2 with tumor microenvironments for humoral immunity and prognosis in patients with breast cancer

AIM: We have previously reported that the serum concentration of anti-HER2 autoantibodies (HER2-AAb) is associated with favorable outcomes in patients with invasive breast cancer (Tabuchi et al., Breast Cancer Res Treat 157:55-63, 2016). This study aimed to investigate the prognostic impact of HER2-AAb by examining the tumor microenvironments for humoral immunity.

PATIENTS AND METHODS: From 500 consecutive patients with invasive breast cancer (Ibid.), we selected those whose log-transformed HER2-AAb values were above mean + 2SD (high HER2-AAb group, N = 33) or below mean − 2SD (low HER2-AAb group, N = 20). Tumor formalin-fixed paraffin-embedded (FFPE) samples and regional lymph node FFPE samples prepared from the patients’ surgical specimens were subjected to immunohistochemistry. Tumor-infiltrating immune cells (ICs) localized inside the tumor, in the adjacent stroma, and in the tumor stroma were separately counted. Expression of some proteins in tumor cells (TCs) was evaluated by the percentages of tumor cells showing presence of those proteins.

RESULTS: We confirmed in the selected patients that the recurrence-free interval of the high HER2-AAb group was significantly longer than that of the low HER2-AAb group (log-rank P = 0.017; hazard ratio = 0.12). Tumor-infiltrating CD20-positive ICs (intratumoral + adjacent stromal ICs, P &lt; 0.001), IGKC-positive ICs (intratumoral + adjacent stromal ICs, P = 0.023), and CXCL13-positive ICs (total ICs, P = 0.044) were significantly greater in the high HER2-AAb group than in the low HER2-AAb group. CD4-positive ICs in B-cell follicles of the regional lymph nodes were also significantly greater in the high HER2-AAb group than in the low HER2-AAb group (P = 0.026). Tumor-infiltrating PD-L1-positive ICs, CD8-positive ICs, FOXP3-positive ICs, as well as CD8/FOXP3 ratios, were not significantly different between the two groups. The expression of CXCL13, HLA-A/B/C, and PD-L1 in TCs was not significantly different between the two groups. The repertoire of B-cell receptors in ICs was not significantly different between the two groups but was considered to be skewed. HER2 expression and gene amplification and the existence of HER2 missense mutations were similar between the two groups.

CONCLUSIONS: Increased HER2-AAb concentration was associated with enhanced humoral immunity in tumor microenvironments. Our findings indicate that a patient subpopulation with enhanced humoral immunity protecting against breast cancer recurrence exists. The recognition site of HER2-AAb may not be located in the HER2 polypeptide, but may be located in modifying factors, such as sugar chains.

Citation Format: Masafumi Shimoda, Yasufumi Sato, Yoshiaki Sota, Tomohiro Miyake, Tomonori Tanei, Naofumi Kagara, Yasuto Naoi, Kenzo Shimazu, Seung Jin Kim, Shinzaburo Noguchi. Association of autoantibodies to HER2 with tumor microenvironments for humoral immunity and prognosis in patients with breast cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1604.

Development of Prediction Model Including MicroRNA Expression for Sentinel Lymph Node Metastasis in ER-Positive and HER2-Negative Breast Cancer

BACKGROUND

The aim of our study is to find microRNAs (miRNAs) associated with sentinel lymph node metastasis (SLNM) and to develop a prediction model for SLNM in ER-positive and HER2-negative (ER+/HER2-) breast cancer.

PATIENTS AND METHODS

In the present study, only ER+/HER2- primary breast cancer was considered. The discovery set for SLNM-associated miRNAs included 10 tumors with and 10 tumors without SLNM. The training and validation sets both included 100 tumors. miRNA expression in tumors was examined comprehensively by miRNA microarray in the discovery set and by droplet digital PCR in the training and validation sets.

RESULTS

In the discovery set, miR-98, miR-22, and miR-223 were found to be significantly (P < 0.001, fold-change > 2.5) associated with SLNM. In the training set, we constructed the prediction model for SLNM using miR-98, tumor size, and lymphovascular invasion (LVI) with high accuracy (AUC, 0.877). The accuracy of this prediction model was confirmed in the validation set (AUC, 0.883), and it outperformed the conventional Memorial Sloan Kettering Cancer Center nomogram. In situ hybridization revealed the localization of miR-98 expression in tumor cells.

CONCLUSIONS

We developed a prediction model consisting of miR-98, tumor size, and LVI for SLNM with high accuracy in ER+/HER2- breast cancer. This model might help decide the indication for SLN biopsy in this subtype.

Radiogenomics of magnetic resonance imaging and a new multi-gene classifier for predicting recurrence prognosis in estrogen receptor-positive breast cancer: A preliminary study

To examine the correlation of qualitative and quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) results with 95-gene classifier or Curebest 95-gene classifier Breast (95GC) results for recurrence prediction in estrogen receptor-positive breast cancer (ERPBC).This retrospective study included 78 ERPBC patients (age range, 24-74 years) classified into high- (n = 33) and low- (n = 45) risk groups for recurrence based on 95GC and who underwent DCE-MRI between July 2006 and November 2012. For qualitative evaluation, mass shape, margin, and internal enhancement based on BI-RADS MRI lexicon and multiplicity were determined by consensus interpretation by 2 breast radiologists. For quantitative evaluation, mass size, volume ratios of the DCE-MRI kinetics, and both the kurtosis and the skewness of the intensity histogram for the whole mass in the initial and delayed phases were determined. Differences between the 2 risk-groups were analyzed using univariate logistic regression analyses and multiple logistic regression analyses. Receiver-operating characteristic curve cut-off values were used to define the groups.As for the qualitative findings, the difference between the 2 groups was not significant. For the quantitative data, the volume ratio of "medium" in the initial phase differed significantly between the 2 groups (P = .049). The volume ratio of "medium" (P = .006) and of "slow-persistent" (P = .005), and the delayed phase kurtosis (P = .012) in the univariate logistic regression analyses, and in the multiple logistic regression, volume ratio of "medium" >38.9% and delayed phase kurtosis >3.31 were identified as significant high-risk indicators (odds ratio, 5.83 and 3.55; 95% confidence interval, 1.58 to 21.42 and 1.24 to 10.15; P = .008 and P = .018, respectively).A high volume ratio of "medium" in the initial phase and/or high kurtosis in the delayed phase for quantitative evaluation could predict high ERPBC recurrence risk based on 95GC.

Highly sensitive detection of sentinel lymph node metastasis of breast cancer by digital PCR for RASSF1A methylation

One-step nucleic acid amplification (OSNA) targeting cytokeratin 19 (CK19) mRNA expression and pathological examination are widely used for the intraoperative diagnosis of sentinel node (SN) metastasis. The aim of the present study was to develop a novel assay for detecting SN metastasis by targeting Ras association domain-containing protein 1 (RASSF1A) methylation in tumor cells, and to compare its performance with OSNA. Using digital PCR with methylation-specific restriction enzymes (RE-dMSP), our assay was able to detect ≥3 copies of methylated DNA per well, and was ≥10 times more sensitive than real-time PCR with bisulfite modification. OSNA lysates were examined using RE-dMSP and digital PCR for PIK3CA mutation, in the event that primary tumors were PIK3CA mutation-positive. RE-dMSP revealed a high concordance of 95.0% (153/161) with OSNA, and 100% (59/59) with PIK3CA mutation for detecting SN metastasis. In 11 breast cancer cell lines, the variation in methylated RASSF1A copy number was significantly lower than that of CK19 mRNA (2.8 vs. 10.5-fold; P<0.01). RE-dMSP has the potential to more accurately detect SN metastasis, and to more precisely estimate total tumor loads in SN, compared with OSNA.

Development of recurrence risk score using 95‑gene classifier and its application to formalin‑fixed paraffin‑embedded tissues in ER‑positive, HER2‑negative and node‑negative breast cancer

We previously developed a 95‑gene classifier (95GC) to classify ER‑positive/HER2‑negative/node‑negative (ER+/HER2‑/N0) breast cancer as high‑ and low‑risk. The present study aimed to devise a 95GC recurrence score (95GCRS) to estimate recurrence risk more precisely and, although the 95GC was originally developed using fresh‑frozen (FF) tissues, this was applied to formalin‑fixed paraffin‑embedded (FFPE) tissues. 95GCRS was calculated using between‑group analysis and denominated as a value from 0 to 100. Correlation of 95GCRS with distant recurrence rate and response to neoadjuvant chemotherapy (NAC) was evaluated in 257 patients with ER+/HER2-/N0 breast cancer treated with adjuvant hormonal therapy at Osaka University Hospital and in 425 patients with ER+ breast cancer treated with NAC at Osaka University Hospital and the University of Texas MD Anderson Cancer Center (GSE25066 dataset). Correlation of 95GCRS between FF and FFPE tissues was evaluated in paired tissues from 56 ER+/HER2‑/N0 breast cancer types obtained from patients without NAC treatment. Distant recurrence rates were remarkably low in patients with 95GCRS ≤50 and increased proportionally in patients with 95GCRS >50. Pathological complete response (pCR) rates to NAC were increased in proportion to 95GCRS, indicating a greater sensitivity of breast cancers with high 95GCRS to chemotherapy. 95GCRS was highly correlated (R=0.92) between FF and FFPE tissues, and the concordance rate (94.6%) of high‑ and low‑risk groups was also considerably high. Overall, the present study developed a 95GCRS that correlated with distant recurrence rate and pCR rate to NAC. The 95GC was applicable to FFPE tissues with a high concordance rate in FF tissues.

Real-Time Visualization of Lymphatic Flow to Sentinel Lymph Nodes by Contrast-Enhanced Ultrasonography with Sonazoid in Patients with Breast Cancer

Contrast-enhanced ultrasonography with Sonazoid (SNZ) enables real-time visualization, resulting in more precise identification of lymphatic flow to sentinel lymph nodes (SLNs). This study aimed to classify lymphatic drainage patterns to SLNs. Patients (n = 75) with T1-2 N0 M0 breast cancer received a periareolar injection of SNZ to identify SNZ-enhanced SLNs (SNZ-SLNs), followed by SLN biopsy with blue dye. The lymphatic drainage patterns were classified into four types: type A, single lymphatic route/single SLN; type B, multiple lymphatic routes/single SLN; type C, single lymphatic route/multiple SLNs; and type D, multiple lymphatic routes/multiple SLNs. SLNs were successfully identified in all patients using both blue dye and SNZ. The drainage lymphatic pathways identified were as follows: type A in 53 cases (70.7%), type B in seven (9.3%), type C in eight cases (10.7%) and type D in seven (9.3%). SNZ-SLN biopsy is a technically simple method with a 100% identification rate, enabling the real-time visualization of lymphatic flow to SNZ-SLNs.

Vasculogenic mimicry is associated with trastuzumab resistance of HER2-positive breast cancer

Background

Trastuzumab is a drug that targets the receptor tyrosine kinase HER2 and is essential for the treatment of HER2-positive breast cancer. Resistance to the drug leads to severe consequences, including disease recurrence, tumor enlargement, and metastasis. We hypothesized that trastuzumab treatment might be associated with phenotypic switching in HER2-positive breast cancer cells (BCCs), enabling them to escape and survive the effect of trastuzumab.

Methods

We conducted comprehensive immunophenotyping to detect phenotypic changes in HER2-positive BCCs treated with trastuzumab, based on criteria determined a priori. Based on immunophenotyping results, we characterized the vascular phenotypes of HER2-positive BCCs by western blotting, real-time RT-PCR, and tube formation assay. The vascular phenotype of tumor cells from clinical samples was evaluated by staining with periodic acid-Schiff and an anti-CD31 antibody. We explored small molecule inhibitors that suppress tube formation and determined the inhibitory mechanism.

Results

Out of 242 cell surface antigens, 9 antigens were significantly upregulated and 3 were significantly downregulated by trastuzumab treatment. All upregulated antigens were related to endothelial and stem cell phenotypes, suggesting that trastuzumab treatment might be correlated to switching to a vascular phenotype, namely, vasculogenic mimicry (VM). Several VM markers were upregulated in trastuzumab-treated cells, but these cells did not form tubes on Matrigel, a functional hallmark of VM. Upon analysis of three trastuzumab-resistant HER2-positive cell lines, we found that all three cell lines showed tube formation on Matrigel in the presence of angiogenic growth factors including EGF, FGF2, IGF1, or VEGF. Clinically, VM channels significantly increased in surviving cancer cell clusters of surgically removed tumors pretreated with trastuzumab and chemotherapy compared to both surgically removed tumors without prior systemic treatment and tumors biopsied before presurgical treatment with trastuzumab. Finally, we found that salinomycin completely suppressed VM in all three trastuzumab-resistant cell lines through disruption of actin cytoskeletal integrity.

Conclusions

VM promotes metastasis and worsens patient outcomes. The present study indicates that HER2-positive BCCs can exhibit VM in an angiogenic microenvironment after eventually acquiring trastuzumab resistance. The clinical finding supports this in vitro observation. Thus, targeting VM might provide a therapeutic benefit to patients with HER2-positive breast cancer.

Electronic supplementary material

The online version of this article (10.1186/s13058-019-1167-3) contains supplementary material, which is available to authorized users.

A novel 95-gene signature (Curebest 95GC Breast) that predicts recurrence-risk in patients with ER-positive, HER2-negative, node-negative, early-stage primary invasive breast cancer with an intermediate Oncotype DX Recurrence Score

542

Background: The TAILORx trial demonstrated that adjuvant endocrine and chemoendocrine therapies had similar efficacy in patients with hormone receptor-positive, HER2-negative, node-negative breast cancer with an Oncotype DX recurrence score (RS) of 11-25. However, a predictive strategy is needed to identify patients with intermediate RS who may benefit from adjuvant chemoendocrine therapy. Curebest 95GC Breast (95GC) is a 95-gene signature that can stratify patients into two groups with high (95GC-H) and low (95GC-L) groups to predict the risk of recurrence. Our primary objective was to show that 95GC can classify patients with intermediate RS into binary recurrence risk groups. Methods: Patients with ER-positive, HER2-negative, node-negative invasive breast cancer and RS 11-30 who underwent definitive surgery and adjuvant endocrine therapy were included. RNA was derived from archived formalin-fixed, paraffin-embedded samples, and 95GC was calculated as reported previously. The Fisher exact and Brunner-Munzel tests were used to compare variables between 95GC groups. A Kaplan-Meier estimate with a log-rank test was used for recurrence-free survival (RFS) analysis. Results: The analysis included 178 patients from five institutions. The 5-year RFS rate in patients with RS 18-30 was higher in the 95GC-L group (n = 129, 96.3%) than in the 95GC-H group (n = 49, 90.9%; p = 0.002), which was consistent with results in an independent Japanese population (n = 224; p < 0.001). RFS rates significantly differed between the groups among patients with RS 11-25 as well (95GC-L, 97.4%; 95GC-H, 87.1%; p = 0.001). RFS rates did not differ between patients with RS 18-25 (94.8%) and those with RS 26-30 (93.8%; p = 0.33). Conclusions: 95GC can predict recurrence risk in patients with ER-positive, HER2-negative, node-negative invasive breast cancer and intermediate RS. Further prospective retrospective studies in the TAILORx population are warranted to confirm that 95GC can identify patients who may benefit from adjuvant chemoendocrine therapy.

Prognostic value of tumor cell DNA content determined by flow cytometry using formalin-fixed paraffin-embedded breast cancer tissues

PURPOSE

The use of formalin-fixed paraffin-embedded (FFPE) tumor tissues in flow cytometry (FCM)-based determination of tumor cell DNA content is more complicated than the use of fresh-frozen tissues. This study aimed to accurately measure tumor cell DNA content from FFPE tissues by separating tumor cells from stromal cells through FCM and investigating its prognostic impact.

METHODS

We separately measured the DNA contents of tumor cells and stromal cells by gating with pan-cytokeratin and vimentin (FCM^C/V). We evaluated tumor cell DNA contents [DNA index (DI)] of 290 FFPE tumor tissues and classified them into low and high DI groups, using a cutoff DI value determined through an unbiased computational method.

RESULTS

The distribution of DI was bimodal, and a cutoff value was determined at a DI of 1.26. The high-DI tumors were associated with aggressive phenotypes and had significantly worse distant recurrence-free intervals (DRFI) than low-DI tumors. Multivariate analysis revealed that lymph node metastasis, Ki67, and DI were independent factors affecting DRFI. Accordingly, patients with low-DI/low-Ki67 tumors had excellent outcomes compared with other tumor types. Multiploid tumors were associated with increased lymphocytic infiltration and aggressive phenotypes.

CONCLUSIONS

The DI of FFPE tumors could be precisely determined through FCM^C/V. A combination of DI and Ki67 analyses may be able to predict the prognoses of breast cancer patients with greater accuracy.

Application of Burow's solution for cement foreign body in the external auditory canal

INTRODUCTION

Only two reports in English literature have described cement foreign bodies in the external auditory canal.

CASE SUMMARY

We present the case of a 37 year-old man with cement foreign body in the right external auditory canal. Removal of the foreign body was difficult because of severe adhesion to the external auditory canal and tympanic membrane. We therefore used acidic Burow's solution to dissolve the alkaline cement deposition. Application of Burow's solution immediately caused the deposition to take on a paste-like consistency that was easily removed.

DISCUSSION

Burow's solution seems useful for removing cement foreign bodies in the external auditory canal.

Diagnostic Utility of Third-Look, Contrast-Enhanced Sonography Followed by Needle Biopsy for MRI, But Not Second-look Ultrasonography-detected Breast Lesions

BACKGROUND/AIM

To clarify the diagnostic utility of third-look, contrast-enhanced ultrasonography (CEUS) for MRI-detected breast lesions undetectable by unenhanced, second-look ultrasonography (MRI+/US- lesions).

PATIENTS AND METHODS

Clinical stage 0-IIA breast cancer patients who underwent CEUS for incidental MRI+/US- lesions (n=27; cohort 1) and patients with breast lesions detected only by MRI, to be examined by CEUS (n=15; cohort 2), were retrospectively analyzed.

RESULTS

Of the 42 MRI+/US- lesions, 23 (55%) were detected by CEUS and then examined by needle biopsy. Pathological examination showed that 10 of these 23 lesions were malignant. None of the 19 lesions undetected by CEUS were found to be histologically malignant or developed malignancy with a median follow-up of 18.5 months. The accuracy, sensitivity, and specificity of CEUS plus needle biopsy were 98%, 91%, and 100%, respectively.

CONCLUSION

Third-look CEUS followed by needle biopsy is useful in the initial diagnosis of MRI+/US- lesions.

Construction of a novel multi-gene assay (42-gene classifier) for prediction of late recurrence in ER-positive breast cancer patients

PURPOSE

Prediction models for late (> 5 years) recurrence in ER-positive breast cancer need to be developed for the accurate selection of patients for extended hormonal therapy. We attempted to develop such a prediction model focusing on the differences in gene expression between breast cancers with early and late recurrence.

METHODS

For the training set, 779 ER-positive breast cancers treated with tamoxifen alone for 5 years were selected from the databases (GSE6532, GSE12093, GSE17705, and GSE26971). For the validation set, 221 ER-positive breast cancers treated with adjuvant hormonal therapy for 5 years with or without chemotherapy at our hospital were included. Gene expression was assayed by DNA microarray analysis (Affymetrix U133 plus 2.0).

RESULTS

With the 42 genes differentially expressed in early and late recurrence breast cancers in the training set, a prediction model (42GC) for late recurrence was constructed. The patients classified by 42GC into the late recurrence-like group showed a significantly (P = 0.006) higher late recurrence rate as expected but a significantly (P = 1.62 × E-13) lower rate for early recurrence than non-late recurrence-like group. These observations were confirmed for the validation set, i.e., P = 0.020 for late recurrence and P = 5.70 × E-5 for early recurrence.

CONCLUSION

We developed a unique prediction model (42GC) for late recurrence by focusing on the biological differences between breast cancers with early and late recurrence. Interestingly, patients in the late recurrence-like group by 42GC were at low risk for early recurrence.

LATS2 promoter hypermethylation and its effect on gene expression in human breast cancer

Tumor-specific promoter hypermethylation of large tumor suppressor, homolog 2 (LATS2), a tumor suppressor gene, has been investigated using methylation-specific polymerase chain reaction (MSP) assays in different types of human cancer producing conflicting results. The aim of the present study was to evaluate the methylation status of the LATS2 promoter region using bisulfite sequencing with a next generation sequencer for breast cancer. In the 11 patients enrolled in the present study, the LATS2 promoter methylation index (MI) was uniformly high in tumor and normal tissues of the breast (median, 84.0 and 87.4%, respectively). The presence of LATS2 promoter hypermethylation was confirmed in isolated tumor cells and normal epithelial cells using the magnetic-activated cell sorting method. In situ hybridization for LATS2 messenger RNA (mRNA) revealed that the mRNA expression of LATS2 was higher in normal epithelial cells, compared with tumor cells, however, it was not significantly associated with LATS2 MI. In 12 breast cancer cell (BCC) lines and two normal breast cell lines, the LATS2 promoter was uniformly hypermethylated with no correlation between the mRNA expression of LATS2 and the LATS2 MI. In addition, treatment of the BCC lines with a demethylating reagent had minimal effect on the mRNA expression of LATS2 in any of these cell lines. These results demonstrated that LATS2 hypermethylation was not involved in silencing the mRNA expression of LATS2 mRNA. The lower mRNA expression level of LATS2 in tumor cells, compared with normal epithelial cells, suggested the possible involvement of downregulation in the mRNA expression of LATS2 in the pathogenesis of breast cancer. Therefore, the conflicting results previously reported for LATS2 promoter methylation in different types of cancer, detected using MSP assays may be attributable to the low fidelity of the MSP assay.

Endocrine sensitivity of estrogen receptor-positive breast cancer is negatively correlated with aspartate-β-hydroxylase expression

Although prognostic markers for early estrogen receptor (ER)‐positive breast cancer have been extensively developed, predictive markers for adjuvant endocrine therapy are still lacking. Focusing on the mechanisms underlying endocrine resistance, we investigated whether the endocrine sensitivity of ER‐positive breast cancer cells was correlated with the expression of aspartate‐β‐hydroxylase (ASPH), which is involved in the development of hepatocellular carcinoma. ASPH expression in ER‐positive and tamoxifen‐resistant breast cancer cells was upregulated by the MAPK and phosphoinositide‐3 kinase (PI3K) pathways, which both play pivotal roles in endocrine resistance. In the clinical setting, ASPH expression was negatively correlated with recurrence‐free survival of luminal B breast cancer patients that received adjuvant endocrine therapy, but not in patients that did not receive adjuvant endocrine therapy. Luminal B breast cancer is one of the intrinsic molecular subtypes identified by the Prediction Analysis of Microarray 50 (PAM50) multiple gene classifier, and because of its poor response to endocrine therapy, chemotherapy in addition to endocrine therapy is generally required after surgical resection. Our results suggest that the endocrine sensitivity of luminal B breast cancer can be assessed by examining ASPH expression, which promotes the consideration of a prospective study on the association between ASPH expression at the mRNA and protein levels in luminal B breast cancer and subsequent response to endocrine therapy.

Highly sensitive detection of ESR1 mutations in cell-free DNA from patients with metastatic breast cancer using molecular barcode sequencing

PURPOSE

We aimed to develop a highly sensitive method to detect ESR1 mutations in cell-free DNA (cfDNA) using next-generation sequencing with molecular barcode (MB-NGS) targeting the hotspot segment (c.1600-1713).

METHODS

The sensitivity of MB-NGS was tested using serially diluted ESR1 mutant DNA and then cfDNA samples from 34 patients with metastatic breast cancer were analyzed with MB-NGS. The results of MB-NGS were validated in comparison with conventional NGS and droplet digital PCR (ddPCR).

RESULTS

MB-NGS showed a higher sensitivity (0.1%) than NGS without barcode (1%) by reducing background errors. Of the cfDNA samples from 34 patients with metastatic breast cancer, NGS without barcode revealed seven mutations in six patients (17.6%) and MB-NGS revealed six additional mutations including three mutations not reported in the COSMIC database of breast cancer, resulting in total 13 ESR1 mutations in ten patients (29.4%). Regarding the three hotspot mutations, all the patients with mutations detected by MB-NGS had identical mutations detected by droplet digital PCR (ddPCR), and mutant allele frequency correlated very well between both (r = 0.850, p < 0.01). Moreover, all the patients without these mutations by MB-NGS were found to have no mutations by ddPCR.

CONCLUSION

In conclusion, MB-NGS could successfully detect ESR1 mutations in cfDNA with a higher sensitivity of 0.1% than conventional NGS and was considered as clinically useful as ddPCR.

Identification of sentinel lymph nodes by contrast-enhanced ultrasonography with Sonazoid in patients with breast cancer: a feasibility study in three hospitals

The aim of this prospective study was to evaluate the feasibility of periareolar injection of the contrast agent Sonazoid (SNZ) followed by ultrasonography (US) for the identification of sentinel lymph node (SLN) in breast cancer patients with clinically negative node. Patients (n = 100) with T1-2N0M0 breast cancer received a periareolar injection of SNZ followed by US to identify contrast-enhanced SLN. Each contrast-enhanced SLN underwent fine needle aspiration cytology (FNAC) followed by SLN biopsy with a conventional method using blue dye and/or radiocolloid (B/R). In almost all cases, contrast-enhanced lymphatic vessels were clearly visualized by US soon after the periareolar injection of SNZ and the SLNs were easily identified with an identification rate of 98% (98/100) for SNZ and 100% (100/100) for B/R. The number of SLNs identified by SNZ (SNZ-SLN) (mean per patient, 1.52) was significantly lower than that identified by B/R (B/R-SLN) (2.19) (P < 0.0001). Twenty-five patients with positive SLNs had at least one positive SNZ-SLN. On a node-by-node basis, sensitivity, specificity, and accuracy of FNAC for SNZ-SLNs (n = 149) were 33.3%, 99.2%, and 85.9%, respectively. Identification of SLN by periareolar injection of SNZ is a technically simple method with an identification rate as high as 98%. SNZ-SLN thus seems to be a good target for FNAC, but sensitivity of FNAC for SNZ-SLNs needs to be improved.

Methylation of the SEPT9_v2 promoter as a novel marker for the detection of circulating tumor DNA in breast cancer patients

The aim of the present study was to evaluate the promoter methylation status of SEPT9_v2 in breast cancer and to detect this methylated gene in circulating tumor DNA (ctDNA) in plasma. Bisulfite sequencing was performed with a next generation sequencer. Methylation of the SEPT9_v2 promoter was found in 67% (8/12) of breast cancer cell lines and 53% (10/19) of breast tumor tissue, but not in normal breast tissue (0/19). A clear inverse correlation was observed between the expression of SEPT9_v2 mRNA and the methylation index (MI) both in cell lines and breast cancer tissues. The MI of SEPT9_v2 was significantly higher in non-basal subtype of breast cancer (13.0%, n=84) than in basal subtype (3.0%, n=23) (P<0.0001). Methylated SEPT9_v2 ctDNA in plasma was detected in 11% (9/82) of primary breast cancer patients and 52% (26/50) of metastatic breast cancer patients, but not in the healthy controls (0/51). These results indicate that SEPT9_v2 promoter hypermethylation, which silences the expression of SEPT9_v2 mRNA, is observed in a significant proportion of breast tumors, and that methylated SEPT9_v2 may serve as a novel tumor marker for breast cancer.

Correlation of Methylated Circulating Tumor DNA With Response to Neoadjuvant Chemotherapy in Breast Cancer Patients

BACKGROUND

Circulating tumor DNA (ctDNA) is known to harbor tumor-specific genetic or epigenetic alterations. In the present study, the correlation of ctDNA with tumor response to neoadjuvant chemotherapy (NAC) was evaluated in primary breast cancer patients.

PATIENTS AND METHODS

Plasma samples were obtained from 87 primary breast cancer patients (stage II-III) before and after NAC, as well as 1 year after surgery. Methylated ctDNA (met-ctDNA) was determined by one-step methylation-specific PCR (OS-MSP) for the promoter region of RASSF1A.

RESULTS

The positivity (23.0%, 20/87) of met-ctDNA before NAC was significantly (P < .05) higher than that of carcinoembryonic antigen (CEA) (8.6%) and cancer-associated antigen (CA) 15-3 (7.4%). In the patients with positive met-ctDNA before NAC, met-ctDNA significantly decreased after NAC in those with disease that responded to therapy (P = .006), but not in patients whose disease did not respond to therapy. Met-ctDNA after NAC was found to be significantly (P = .008) correlated to the extent of residual tumor burden. Of the 7 patients who showed an increase in met-ctDNA at 1 year after surgery, 3 developed recurrence.

CONCLUSION

Met-ctDNA is a more sensitive marker than CEA and CA15-3, and it might be useful in monitoring the clinical tumor response to NAC. In addition, the potential use of met-ctDNA as a tumor marker for monitoring postoperative recurrence has been suggested.

Abstract P3-06-05: Importance of TGFβ-SMAD3 axis in resistance to anti-HER2 drugs

Aim: The aim of this study was to elucidate the role of transforming growth factor β (TGFβ) in the resistance of HER2-positive breast cancer cells to anti-HER2 drugs including trastuzumab and lapatinib.

Methods: A HER2-positive breast cancer cell line, SKBR3, was cultured in the presence or absence of TGFβ for 14 days. Subsequently, TGFβ-treated cells were cultured for seven days with or without the anti-HER2 drugs. Sensitivity to trastuzumab and lapatinib was estimated by the WST-8 cell viability assay or absolute cell counts using In Cell Analyzer (GE Healthcare). Proportion of CD44+ CD24– breast cancer stem cells was estimated by flow cytometry of cells immunostained with anti-CD44 and anti-CD24 antibodies. For clinical study, 33 patients with HER2-positive breast cancer receiving neoadjuvant paclitaxel plus trastuzumab in our institution were analyzed. Among the cases, 27 biopsy samples obtained before any treatment from 27 patients who completed 12 cycles of weekly paclitaxel and trastuzumab were subjected to CD24 immunohistochemistry.

Results: SKBR3 cells cultured with TGFβ for 14 days exhibited decreased sensitivity to both trastuzumab and lapatinib. Time course study revealed that continuous stimulation for 14 days with TGFβ was required for the resistance to anti-HER2 drugs. Activation of SMAD3, a downstream target molecule of TGFβ, was enhanced over time, judged by the increase in phosphorylation and in nuclear translocation. During 14 day culture with TGFβ, proportion of CD44+ CD24– cells were dramatically increased, and mammosphere formation, another marker of breast cancer stem cells, was significantly enhanced compared to cells treated without TGFβ. Among four HER2-positive breast cancer cell lines, only SKBR3 cells showed increased proportion of CD44+ CD24– cells and resistance to the anti-HER2 drugs, while other two cell lines exhibited epithelial-mesenchymal transition (EMT) in response to TGFβ. To explore the possibility of targeting TGFβ-SMAD3 axis to overcome resistance to anti-HER2 therapy, we used SIS3, a specific inhibitor of SMAD3. Importantly, SIS3 completely restored the sensitivity to both trastuzumab and lapatinib of TGFβ-treated SKBR3 cells, with the decrease in the proportion of CD44+ CD24– cells. These in vitro results suggest that CD24 downregulation can be a surrogate marker of resistance to anti-HER2 therapy. To establish this, we evaluated the CD24 expression in tumor samples of breast cancer patients who received paclitaxel plus trastuzumab in the neoadjuvant setting. Weak CD24 expression in tumor cells in biopsy samples obtained before any treatment was significantly correlated with poorer response to the drugs.

Conclusion: These data clearly indicate the importance of TGFβ-SMAD3 axis in the acquired resistance to anti-HER2 drugs. Moreover, resistance to anti-HER2 therapy is associated with the property of breast cancer stem cells rather than EMT. Targeting TGFβ-SMAD3 axis warrants further investigation for overcoming resistance to anti-HER2 therapeutics.

Citation Format: Shimoda M, Chihara Y, Kagara N, Naoi Y, Shimomura A, Shimazu K, Kim SJ, Noguchi S. Importance of TGFβ-SMAD3 axis in resistance to anti-HER2 drugs. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-06-05.

Loss of imprinting of IGF2 in fibroadenomas and phyllodes tumors of the breast

Loss of imprinting (LOI) of insulin-like growth factor 2 (IGF2) is thought to be implicated in the pathogenesis of some tumors by upregulating IGF2 mRNA but its role in the pathogenesis of fibroadenomas (FAs) and phyllodes tumors (PTs) of the breast is yet to be studied. LOI of IGF2 was investigated in 25 FAs and 17 PTs which were heterozygous for Apa I polymorphism, and was found to be present in 13 FAs and 12 PTs. IGF2 mRNA expression was more upregulated in FAs and PTs than in paired surrounding normal tissues and laser microdissection showed that IGF2 mRNA expression was significantly higher in the stromal than the epithelial cells. LOI was not associated with upregulation of IGF2 mRNA, nor were MED12 mutations and methylation status of the differentially methylated region 0 (DMR0) of IGF2. These results demonstrate that IGF2 mRNA expression is more upregulated in FAs and PTs than in normal tissues, especially in their stromal cells, but such an upregulation is not related to LOI of IGF2, and that hypomethylation of DMR0 is unlikely to be involved in induction of LOI.

Prediction of pathological complete response to neoadjuvant chemotherapy by magnetic resonance imaging in breast cancer patients

The purpose of this study was to evaluate whether the baseline breast MRI findings would be useful for the prediction for pathological complete response (pCR) by breast cancer patients to neoadjuvant chemotherapy. Primary breast cancer patients (stage II-III) preoperatively treated with sequential paclitaxel (12 cycles) and fluorouracil, epirubicin, and cyclophosphamide (4 cycles), followed by surgery were retrospectively enrolled, and 229 patients were eligible. Before chemotherapy, breast MRI studies were performed. Breast tumors were dichotomized into round + oval and irregular types based on MRI morphology. The round + oval tumors showed a significantly higher pCR rate than the irregular tumors (42.0% vs 17.3%; P < 0.001). In addition, PAM50 analysis revealed that basal and HER2-enriched tumors were significantly more prevalent among round + oval than irregular type tumors (P = 0.015). Baseline MRI morphology appears to be a significant predictor for pCR. The higher rate of the basal and HER2-enriched tumors among the round + oval tumors may explain their better chemo-sensitivity.

Promoter methylation of TRIM9 as a marker for detection of circulating tumor DNA in breast cancer patients

The aim of the present study was to investigate the promoter methylation status of TRIM9 in breast cancer and to determine the presence of TRIM9-methylated circulating tumor DNA (ctDNA) in plasma. Bisulfite sequencing with a next generation sequencer showed TRIM9 promoter methylation in 92 % (11/12) of breast cancer cell lines (BCCs) and 68 % (13/19) of breast tumor tissues but not in any normal breast tissues (0/19). Methylation ratio of TRIM9 was significantly lower in basal type (9 %, n = 23) than luminal A (69 %, n = 29, P = 0.0003). Quantitative RT-PCR of BCCs disclosed an inverse correlation between TRIM9 mRNA expression and methylation ratio. TRIM9 methylated ctDNA in plasma was detected in 18 % (10/56) of metastatic breast cancer patients but not in any of 60 healthy controls. These results indicate that TRIM9 promoter hypermethylation, which suppresses TRIM9 mRNA expression, occurs in a significant proportion of breast tumors, and that TRIM9-methylated ctDNA thus may serve as a tumor marker for breast cancer.

One-Step Nucleic Acid Amplification Assay for Detection of Axillary Lymph Node Metastases in Breast Cancer Patients Treated with Neoadjuvant Chemotherapy

BACKGROUND

The accuracy of one-step nucleic acid amplification (OSNA) for the detection of lymph node (LN) metastasis in breast cancer patients has been well established. This study aimed to evaluate its accuracy for patients treated with neoadjuvant chemotherapy (NAC).

METHODS

For this study, 300 LNs, 115 sentinel lymph nodes (SLNs), and 185 non-SLNs from 88 breast cancer patients treated with NAC were examined by means of histology (hematoxylin and eosin staining and pancytokeratin immunostaining) and OSNA.

RESULTS

The diagnostic accuracy, sensitivity, and specificity of OSNA were respectively 92.3, 88.5, and 93.3 % for all LNs, and the corresponding values were 87.8, 75.0, and 91.2 % for SLNs and 95.1, 97.3, and 94.6 % for non-SLNs. The diagnostic accuracy of OSNA was significantly lower for SLNs than for non-SLNs (P = 0.021), which was attributable to the low sensitivity for detection of micrometastases (micromets) due to lower CK19 mRNA expression detected by in situ hybridization (ISH) in SLN micromets than in non-SLN micromets. For primary breast tumors, CK19 mRNA expression showed a significant reduction after NAC (P = 0.040).

CONCLUSIONS

The diagnostic accuracy of OSNA for NAC-treated patients is similar to that for NAC-nontreated patients, but its accuracy is significantly lower for SLNs than for non-SLNs. The findings obtained with CK19 mRNA ISH suggest that most SLN micromets cannot be detected by OSNA due to the reduced expression of CK19 mRNA induced by NAC.

Construction of multi-gene classifier for prediction of response to and prognosis after neoadjuvant chemotherapy for estrogen receptor positive breast cancers

The aims of this study were to develop a multi-gene expression-based prediction model for pathological complete response (pCR) to neoadjuvant chemotherapy (NAC) and to evaluate its prognosis prediction for estrogen receptor (ER) positive breast cancers. The training set included the NAC-treated patients (n = 104) with ER+ breast tumors in our hospital and the validation set included the NAC-treated patients (n = 259) with ER+/HER2- breast tumors in the public database (GSE25066). Gene expression in the tumor biopsy specimens obtained before NAC was analyzed with DNA microarray, and the prediction model (MPCP155) for pCR was constructed for the training set by using the genes (155 probes) involved in the metabolic pathways which the pathway analysis identified as being significantly associated with pathological response. With MPCP155, the tumors in the validation set could be classified into low chemo-sensitive (low-CS) (pCR rate = 2.6%) and high-CS (pCR rate = 15.3%; P = 0.0006) groups. Furthermore, the low-CS group showed a significantly better prognosis than the high-CS group (P = 2.0E-6). Moreover, prognosis prediction by MPCP155 was independent of the residual cancer burden score. MPCP155 may be helpful for decision making regarding the indication for neoadjuvant chemotherapy. In addition, MPCP155 was found to be useful for prognosis prediction for NAC-treated patients with ER+/HER2- tumors.

PIK3CA mutations in serum DNA are predictive of recurrence in primary breast cancer patients

We attempted to develop a highly sensitive and specific method for the detection of circulating tumor DNA (ctDNA) using a digital PCR (dPCR) assay for PIK3CA mutations (i.e., H1047R, E545K, and E542K) in primary breast cancer patients. The sensitivity of the dPCR assay for the mutant alleles was examined using cell lines with PIK3CA mutations and proved to be 0.01 %. Serum samples were collected pre-operatively from 313 stage I-III breast cancer patients, of whom 110 were found to have PIK3CA mutant tumors. The serum samples from these patients with PIK3CA mutant tumors were subjected to the dPCR assay, and 25 (22.7 %) were found to be positive. No PIK3CA mutant ctDNA was detected in the serum samples of 50 healthy women and 30 breast cancer patients with PIK3CA non-mutant tumors. The patients with PIK3CA mutant ctDNA were dichotomized into mutant ctDNA-high (ctDNA(high)) and ctDNA-low (ctDNA(low)) groups based on the median. The ctDNA(high) patients exhibited significantly shorter recurrence-free survival (RFS; P = 0.0002) and overall survival rates (OS; P = 0.0048) compared to those exhibited by the combined ctDNA(low) patient and ctDNA-free patient group. Multivariate analysis revealed that ctDNA(high) status significantly predicted poor RFS and OS and did so independently of conventional histological parameters. These results suggest that dPCR is a highly sensitive and specific method for the detection of PIK3CA mutant ctDNA and that ctDNA(high) but not ctDNA(low) status is a significant and independent prognostic factor for primary breast cancer patients.