Abstract P4-13-16: Impact of immediate breast reconstruction after mastectomy on the outcome of patients receiving neoadjuvant chemotherapy

Background and purpose

In breast cancer patients receiving neoadjuvant chemotherapy (NAC), immediate breast reconstruction (IBR) is controversial. IBR might favor recurrences and metastases due to delayed adjuvant radiation therapy.

We retrospectively investigated whether IBR after mastectomy influenced the outcome of patients receiving neoadjuvant chemotherapy.

Patients and methods

Between 2006 and 2016, 243 breast cancer patients received total mastectomy after NAC, 48 of whom underwent IBR. Patients receiving IBR (IBR group) were compared to patients who did not receive IBR (no-IBR group) over a prolonged median follow-up time (72.3 moths).

The regimen was 4 cycles of epirubicin (100 or 75 mg/m2), 5-fluorouracil (500 mg/m2), and cyclophosphamide (500 mg/m2) followed by 4 cycles of docetaxel (75 mg/m2). Post-mastectomy radiation was applied in cases treated by IBR following the same selection criteria as for standard mastectomy regardless of the reconstruction approach.

Results

Patients in the IBR group were on average younger than patients in no-IBR

group (p<0.001). The percentage of patients with clinical T1/2 tumor was 81.2% in the IBR group and 58.4% in no-IBR group (p=0.0042). 2 patients (4.2%) in the IBR group and 9 patients (4.6%) in no-IBR group showed the locoregional recurrences. 2 patients (4.2%) in the IBR group and 20 patients (10.3%) showed distant metastases. There were no significant differences.

Conclusions

IBR after total mastectomy was not associated with worse rate of locoregional recurrences in patients receiving NAC.

Citation Format: Nogi H, Tomita S, Kamio M, Shioya H, Toriumi Y, Takeyama H. Impact of immediate breast reconstruction after mastectomy on the outcome of patients receiving neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-13-16.

Impairment of DYRK2 augments stem-like traits by promoting KLF4 expression in breast cancer

Whereas accumulating studies have supported the cancer stem cell theory, a specific therapy targeting a cancer stem cell subpopulation has not been established. Here, we show that dual-specificity tyrosine phosphorylation-kinase 2 (DYRK2) is a novel negative regulator for formation of breast cancer stem cells. Downregulation of DYRK2 promotes cancer stem-like traits in vitro, tumourigenesis in vivo and the proportion of the cancer stem cell population in human breast cancer tissues. We found that Krupple-like factor 4 (KLF4) serves as a key mediator of DYRK2's control over the cancer stem phenotype. Reduced DYRK2 expression increases KLF4 expression, which induces cancer stem-like properties. We identified androgen receptor (AR) as a transcription factor binding to the KLF4 promoter region; this process is dependent on DYRK2 kinase activity. Our findings delineate a mechanism of cancer stem cell regulation by the DYRK2-AR-KLF4 axis in breast cancer. Targeting of this pathway may be a promising strategy against breast cancer stem cells.

Abstract P5-07-07: DYRK2 contributes to the generation of breast cancer stem cells through KLF4

<Introduction>

Cancer stem cells (CSCs) have been defined by the potential to self-renew and to differentiate. CSCs pose a major hurdle in the treatment of cancer. However, the mechanisms by which cells acquire CSC properties such as drug resistance remain unclear.

Dual-specificity tyrosine-regulated kinase 2 (DYRK2) is a protein kinase that phosphorylates its substrates on serine/threonine. Initially, we found that DYRK2 phosphorylates p53 at Ser 46 to regulate apoptotic cell death in response to DNA damage. Recently, we have shown that DYRK2 controls Snail degradation in breast cancer and ovarian serous adenocarcinoma. We also found that knockdown of DYRK2 in luminal-type breast cancer MCF-7 cells increased the cancer stem cell population.

Kruppel-like factor 4 (KLF4) is one of the Yamanaka factors. It has been reported that pluripotent stem cells from mouse embryonic or adult fibroblasts are induced by introducing four factors, Oct3/4, Sox2, c-Myc, and Klf4. This finding led us to determine if KLF4 is indispensable for the maintenance of CSCs.

The aim of this study is to clarify whether DYRK2 regulates CSCs through KLF4 in breast cancer.

<Methods>

Cell lines: MCF-7 (human mammary carcinoma: ATCC) cells were grown according to standard protocols.

We established stable DYRK2-depleted cells. MCF-7 cells were transfected with pSuper-puro vector (pSuper control) or pSuper-puro DYRK2 shRNAs (shDYRK2) with puromycin to isolate stable cell lines.

In turn, we established both stable DYRK2- and KLF4-depleted cells. shDYRK2 cells were transfected with pSuper-neo vector (pSuper-neo control) or pSuper-neo KLF4 shRNAs (shKLF4) with puromycin and G418. Knockdown of DYRK2 or KLF4 was confirmed by real-time RT-PCR and immunoblotting.

The depleted cells were compared with the control cells using real-time RT-PCR, immunoblotting, flow cytometric analysis, mammosphere assay, xenograft models and immunohistological staining.

<Results>

We analyzed the population of breast cancer stem cells by flow cytometric analysis and in vitro mammosphere assay. The results showed that knockdown of DYRK2 was associated with the increase of CD44+/CD24- cells. While pSuper control cells formed mammospheres, they did in a lesser extent compared to shDYRK2 cells.

In real-time RT-PCR and immunoblotting analysis, stable DYRK2 depletion in MCF-7 cells induced KLF4 accumulation.

We then investigated the effect of KLF4 on stemness by flow cytometric analysis and in vitro mammosphere assay. The results showed that knockdown of KLF4 in shDYRK2 cells reduced the proportion of CD44+/CD24- cells. Whereas shDYRK2/shKLF4 cells formed mammospheres, they did in a lesser extent compared to shDYRK2/pSuper-neo control cells. Moreover, the scale of the mammospheres formed in shDYRK2/shKLF4 cells was significantly smaller, as compared with that in shDYRK2/pSuper-neo control cells.

In xenograft models, the loss of KLF4 protein expression significantly decreased tumor formation.

Immunohistological staining of fifty-nine samples from surgically treated breast cancer patients showed an inverse correlation between DYRK2 and KLF4 expression.

<Conclusion>

These findings revealed that DYRK2 contributes to the generation of breast cancer stem cells through KLF4.

Citation Format: Imawari Y, Mimoto RK, Yamaguchi N, Kamio M, Kato K, Nogi H, Toriumi Y, Uchida K, Takeyama H, Yoshida K. DYRK2 contributes to the generation of breast cancer stem cells through KLF4 [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-07-07.

Abstract P2-07-16: Alcohol consumption increases mammographic density in women aged ≥55 years

Background: Incresed mammographic density is a significant risk factor for breast cancer and decreses the sensitivity of mammography screening. The aim of this study is to examine the factors affecting breast density in Japanese women.

Data sources and methods: Between Apr. 2014 and Mar. 2016, 3492 women were received mammography screening. According to the results of mammography, breast density was categorized as non-dense(BI-RADS 1 and 2, n=1670) and dense(BI-RADS 3 and 4, n=2222) . Logistic regression was used to estimate the odds of having dense breasts by age, body mass index(BMI), alcohol consumption, smoking, parity, menopausal status, dysmenorrhea, hormone use, family history of breast cancer, physical activity, fried foods intake, brightly colored vegetables intake, coffee intake and tea or green tea intake. All statistical tests were two-sided.

Results: There was a statistically significant negative interaction of age(OR=0.97, <0.001), BMI(OR=0.78, <0.001), number of live birth (one; OR=0.77, <0.030, two or more; OR0.37, <0.001), post-menopause(OR=0.6, <0.001) on breast density. On the other, there was a statistically significant positive interaction of alcohol intake(20g or more a day, OR=1.62, 0.026) in dense breast women aged ≥55 years. A trend of bone mineral density ≥80% and dense breast was seen in women aged ≥40 years(OR=0.63, <0.086, n=510).

Results of analysis of factors influencing breast density among all study participants  Odds ratio95% CIPAgeContinuoous variables0.970.95-0.98<0.001BMIContinuoous variables0.780.76-0.80<0.001Alcohol intakenone1.00 0.325 <20g a day1.120.94-1.350.209 ≥20g a day1.210.91-1.600.186Smokingno1.00   yes0.940.71-1.230.644Birth01.00 <0.001 once0.770.61-0.970.030 ≥20.370.31-0.45<0.001Menopausepre1.00   post0.600.47-0.77<0.001Dysminorrheano1.00   yes0.780.41-1.480.446Family history of breast cancerno1.00   yes1.000.81-1.240.991Physical activityno1.00   yes0.890.74-1.070.207Fried foods intakenone1.00 0.087 once two days0.780.60-1.020.068 ≥once a day0.760.51-1.120.166Brightly coloredd vegetablesnone1.00 0.910 once two days0.950.70-1.280.737 ≥once a day0.950.73-1.220.666Coffee intakenone1.00 0.105 once two days1.060.75-1.510.729 ≥once a day1.221.01-1.470.040Tea/Green tea intakenone1.001.01-1.470.098 once two days0.760.55-1.050.097 ≥once a day0.840.70-1.000.055bone mineral density(n=510)<80%1.00    ≥80%0.630.38-1.070.068

Results of analysis of factors influencing breast density in women aged ≥55 years (n=1382)  Odds ratio95% CIPBMI<25kg/m21.00   ≥25kg/m20.300.21-0.44<0.001Birth0  Trend P<0.001 once0.690.46-1.040.0076 ≥two0.310.23-0.41<0.001Alcohol intakenone  0.052 <20g/day1.260.98-1.620.074 ≥20g/day1.621.06-2.480.026

Conclusion: Alcohol consumption increase mammographic breast density in women aged ≥55 years. As both of increased breast density and alcohol consumption have been suggested to increase risk of breast cancer, more cautious mammographic screening should be considered for those women aged ≥55 years.

Citation Format: Uchida K, Ohashi H, Kitano N, Tsunoda K, Nagamatsu T, Sekine C, Imawari Y, Nogi H, Takeyama H. Alcohol consumption increases mammographic density in women aged ≥55 years [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-07-16.

Interleukin-6 released by colon cancer-associated fibroblasts is critical for tumour angiogenesis: anti-interleukin-6 receptor antibody suppressed angiogenesis and inhibited tumour-stroma interaction

Background:

Interleukin-6 (IL-6) has an important role in cancer progression, and high levels of plasma IL-6 are correlated with a poor prognosis in a variety of cancers. It has also been reported that tumour stromal fibroblasts are necessary for steps in cancer progression, such as angiogenesis. There have been few reports of a correlation between fibroblast actions and IL-6 levels. In this study, we examined the correlation between cancer stromal fibroblasts and IL-6 and the utility of IL-6 as a therapeutic target in human colon cancer.

Methods:

The expression levels of IL-6 and VEGF of fibroblasts and cancer cell lines were evaluated using real-time PCR and ELISA. The anti-angiogenic effect of inhibiting IL-6 signalling was measured in an angiogenesis model and animal experiment.

Results:

We demonstrate that stromal fibroblasts isolated from colon cancer produced significant amounts of IL-6 and that colon cancer cells enhanced IL-6 production by stromal fibroblasts. Moreover, IL-6 enhanced VEGF production by fibroblasts, thereby inducing angiogenesis. In vivo, anti-IL6 receptor antibody targeting stromal tissue showed greater anti-tumour activity than did anti-IL6 receptor antibody targeting xenografted cancer cells.

Conclusion:

Cancer stromal fibroblasts were an important source of IL-6 in colon cancer. IL-6 produced by activated fibroblasts induced tumour angiogenesis by stimulating adjacent stromal fibroblasts. The relationship between IL-6 and stromal fibroblasts offers new approaches to cancer therapy.

Abstract P4-06-11: HER2 type DCIS acquires histological diversity by p53 mutation

[Introduction]

It is widely known that breast cancer is a heterogeneous disease of various phenotypes and biological characteristics.

Several studies have identified distinct subtypes of invasive ductal carcinoma by gene expression profiling or staining pattern of estrogen receptor (ER), progesterone receptor (PR), and HER2/neu protein.

Ductal carcinoma in situ (DCIS) is a non-invasive form of breast cancer, and is thought to be the precursor of invasive breast cancer.

One of the most well-known hypothesis shows that breast cancer occurs in a normal terminal duct lobular unit, and a histological continuity exists between the precursor and breast cancer.

The aim of this analysis is to reveal how DCIS acquires histological diversity and progresses to invasive ductal carcinoma.

We hypothesized that p53 gene mutation is responsible for this acquisition of histological diversity, and performed immunohistochemical analysis to pursue this hypothesis.

[Material and methods]

The participants of this study were taken from a database established by Jikei University School of Medicine. Between the period of April 2000 and April 2011, 84 cases of pure DCIS patients underwent operation.

Patients were classified into 4 subtypes by a combination of hormone receptor (HR) status and HER2 status.

The status of ER, PR, HER2, and p53 was determined by immunohistochemical staining.

Tumors with Allred score above 2 ER / PR nuclear staining were classified as ER / PR positive. Tumors with HER2 membranous staining equivalent to 3+ intensity with Hercep test in more than 30% of the cells were scored as overexpression. p53 was defined as positive when nuclear staining was equal to or greater than 10%.

We evaluated histological nuclear atypia to assess histological diversity of DCIS. When DCIS included different type of atypia cells more than 10%, we judged the histological diversity as positive.

[Results]

Patient characteristics are presented in table1.

Patient characteristics number%Age  median (range)55 (31-83)    Receptor status  ER / PR  positive6780negative1720HER2  positive1821negative6679   Subtype  HR+ / HER2-6274HR+ / HER2+56HR- / HER2+1315HR- / HER2-45

The classifications by the immunohistochemical subtype of DCIS are as follows: HR+/HER2- 62 cases (74%), HR+/HER2+ 5 cases (6%), HR-/HER2+ 13 cases (15%), HR-/HER2- 4 cases (5%).

p53 expression in HR-/HER2+ and HR-/HER2- subtype was significantly higher than HR+/HER2- and HR+/HER2+ subtype (p<0.001).

The frequency of histological diversity by nuclear atypia was high in HR+/HER2- and HR-HER2+ subtype (p = 0.009).

In HR-HER2+ subtype, p53 expression was associated with histological diversity (p = 0.021). But in HR-HER2+ subtype, there was no association with p53 expression and histological diversity.

p53 status and histological diversity of DCIS HR+/HER2-HR+/HER2+HR-/HER2+HR-/HER2-pp53     positive5193<0.001negative57441       histological diversity     positive481910.009negative14443       p0.3310.5760.0210.501 

[Conclusion]

This analysis demonstrates that HR-HER2+ subtype DCIS acquires histological diversity by p53 mutation.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-06-11.

Abstract P1-08-17: Impact of claudin-3 and basal-markers expressions on pathological complete response to neoadjuvant chemotherapy and prognosis in triple negative breast cancer

Background

Triple negative breast cancer (TNBC) has responded well in the neoadjuvant setting, with rates of pathologic complete response (pCR) commonly higher than for other breast tumor types. However, more than half of TNBC patients do not achieve a pCR and have a very poor prognosis. Cluster analysis identified 6 TNBC subtypes displaying unique gene expression, including basal-like and a mesenchymal stem-like (claudin-low) subtype. The object of this study was to evaluate the clinical utility of claudin-3 and basal-markers expressions in the prediction of pCR and prognosis in a cohort of breast cancer patients receiving the combination of taxane and anthracycline as neoadjuvant chemotherapy.

Materials and Methods

A prospective data base of 412 Japanese women with stage I/II/III breast cancer who received neoadjuvant chemotherapy was analyzed. The regimens were 6 cycles of concurrent administration of doxorubicin (50 mg/m2) and docetaxel (60 mg/m2) or 4 cycles of epirubicin (100 mg/m2), 5-fluorouracil (500 mg/m2), and cyclophosphamide (500 mg/m2) followed by 4 cycles of docetaxel (100 mg/m2). We performed immunohistochemical staining for ER, PgR, HER2, epidermal growth factor receptor (EGFR), cytokeratin 5/6 and claudin-3 using specimens obtained at diagnosis by core needle biopsy. Based on immunoreactivity, TNBC tumors were classified into basal/claudin-high (BCH), basal/claudin-low (BCL), non-basal/claudin-high (NBCH) and non-basal/claudin-low (NBCL).

Results

The overall pCR of this patient cohort was 19%. pCR was observed 30 cases of 84 TNBC (36%) and 50 cases of 328 non-TNBC (15%)(p<0.0001). Among the TNBC tumors, pCR rate was significantly different between subgroups. BCH 50%, BCL 23%, NBCH 83% and NBCL 43% (p = 0.039). The 5-year overall survival rate was significantly different between TNBC and non-TNBC. TNBC 81% and non-TNBC 94% (p = 0.0017). The 5-year overall survival rate was different between triple-negative subgroups. BCH 92%, BCL 78%, NBCH 83% and NBCL 46%.

Conclusions

This study indicated that claudin-3 and basal-markers might be predictive biomarkers of pCR and prognosis in triple negative breast cancer patients treated with neoadjuvant chemotherapy.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-08-17.

NOTCH1 expression predicts patient prognosis in esophageal squamous cell cancer

PURPOSE

The prognosis of patients with esophageal cancer remains poor, and the classification of tumor node metastasis has proven insufficient to predict patient prognosis. Therefore, novel predictive markers of esophageal cancer prognosis are needed. Notch receptors and their ligands have been reported to be upregulated in cervical, lung, colon, renal, and pancreatic cancers, but NOTCH1 expression has not been studied in esophageal cancer.

METHODS

Expression of NOTCH1 was quantified by real-time reverse transcription-polymerase chain reaction in 55 primary esophageal squamous cell carcinomas (ESCCs) and their paired normal esophageal mucosa. We then examined the correlations between NOTCH1 expression, clinicopathological factors, and prognosis in patients with ESCC.

RESULTS

The probability of overall survival was significantly lower for patients with high NOTCH1 expression (p = 0.0028; log-rank test). Overexpression of NOTCH1 was identified as a significant and independent prognostic factor (p = 0.0061) in patients who had undergone surgical treatment for ESCCs. The hazard ratio for predicting early death was 4.298 (95% confidence interval 1.515-12.195) for high versus low NOTCH1 expression.

CONCLUSIONS

Our data indicate that NOTCH1 may be a candidate molecular prognostic marker and a molecular target for the development of an effective therapeutic intervention for patients with ESCC.

Abstract P4-03-10: Sonographic-pathological correlation in contrast-enhanced ultrasonography in the diagnosis of breast cancers

Background: As contrast-enhanced ultrasonography (CEUS) in the diagnosis of breast masses has been performed less frequently than other imaging modalities, it's efficacy evaluation has not been established. CEUS with Sonazoid, which is microbubble-based contrast agent, allows visualization of the mass bloodstream, therefore the classification of enhancement patterns in CEUS could increase diagnostic yield for breast masses. To achieve this, a clear standard for the CEUS evaluation is needed. The purpose of this study was to identify CEUS findings for malignancies and clarify sonographic-pathological correlation of breast cancers.

Material and Method: Present study included 20 patients with invasive ductal cancer who underwent operation for primary therapy without any chemotherapy or hormonal therapy. We contrasted CEUS features with Sonazoid with surgical specimens retrospectively. As malignant findings, the presence of focal perfusion defects inside masses and enhancement of outside masses were chosen.

Result: All of the 20 cases displayed focal perfusion defects. 9 cases of those could be successfully assessed in the same sections histopathologically and ultrasonographically. Histopathological findings showed those defects to be fibrotic foci inside masses in 7cases (77.7%). While, 6 cases of all (30%) showed stains outside tumor, and only one case was found out to be fibrotic growth with cancer cells.

Conclusion: focal perfusion defects of breast masses in CEUS were considered to be specific for malignancy, and they seemed to be fibrotic foci histopathologically. Desmoplastic reaction has been observed in epithelial solid tumor biology, and if those defects reflect the desmoplasia defects could be the proof of malignancy.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-03-10.

Abstract P5-04-02: DYRK2 regulates breast cancer invasion via Snail/E-cadherin pathway

Introduction: Epithelial-Mesenchymal Transition (EMT) is characterized by the loss of cellular adhesion molecule E-cadherin, and plays a fundamental role during early steps of breast cancer invasion. An important regulator of E-cadherin expression is Snail, a zinc finger transcriptional repressor. Snail is posphorylated by GSK3β and then degraded by βTrCP mediated ubiquitination. Here we found another kinase, DYRK2, regulates the stability of Snail. Knockdown of DYRK2 promoted the EMT and cancer invasion both in vitro and in vivo experiments.

Methods: Cell lines: MCF-7 cells were transfected with pSuper vector (pSuper control) and pSuper shRNA DYRK2 (shRNA-DYRK2) with G418 to isolate stable cell lines.

Immunoblotting: Expression of pertinent molecular markers was determined by western blotting.

RT-PCR: RNA was extracted using TRIsure and 500 ng of total RNA was amplified using Primer Script One Step RT-PCR Kit Ver.2.

Invasion assay: Various cancer cell lines were seeded on the top of the upper chamber with serum free medium while the bottom chambers were filled with medium containing 10% FBS.

In vivo metastasis assay: Cells in PBS were injected into the left ventricle of 7-week-old female nude mice. Metastases to distant organs were confirmed by IVIS2000.

Immunohistochemistry: We acquired paraffin-embedded tissue sections from primary breast tumor cores and from Jikei University of Medicine. Immunohistochemistry for DYRK2 was performed.

Results: In MCF-7 cells, knockdown of DYRK2 increased Snail in the protein level but not in mRNA level. Upon DYRK2 knockdown, MG132 treatment had no effect on additional increase in Snail. DYRK2 knockdown decreased Snail ubiquitination. Stable DYRK2 depletion led to Snail accumulation and E-cadherin abrogation. Fibroblast marker, Vimentin, emerged in DYRK2 depleted cells. For further analysis, we carried out invasion assays. The invasion potential in DYRK2-depleted cells was substantially higher than that in control cells. In xenograft model, we used nude mice received intracardial injections of pSuper control or shRNA-DYRK2 cells. 6 weeks after injections, a significant increase in bone and lung metastasis was observed in shRNA-DYRK2 group. The patients with tumors expressed low DYRK2 showed significantly poor prognosis.

Conclusion: In breast cancer cells, Snail is phosphorylated by DYRK2 and then acquires the ability to be ubiquitinated. In the absence of DYRK2, Snail is unable to be degraded by ubiquitin-proteasome machinery. Accumulation of Snail promotes EMT and cancer invasion, so low expression of DYRK2 leads to poor prognosis in breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-04-02.

Production of antioxidant vitamins, beta-carotene, vitamin C, and vitamin E, by two-step culture of Euglena gracilis Z

Euglena gracilis Z is one of the few microorganisms which simultaneously produces antioxidant vitamins such as beta-carotene and vitamins C and E. Photoheterotrophically cultured E. gracilis Z produced larger levels of biomass but with a lower content of antioxidant vitamins than photoautotrophically grown cultures. For efficient production of these vitamins, a two-step culture was performed. Cells were grown photoheterotrophically and then transferred to photoautotrophic conditions. When E. gracilis Z cells were grown in fed-batch culture under photoheterotrophic conditions, their density reached 19 g/L after 145 h. Subsequent transfer of these cells to photoautotrophic conditions increased vitamin content, enhancing the total vitamin yields, which were 71.0 mg/L of beta-carotene, 30.1 mg/L of vitamin E, and 86.5 mg/L of vitamin C. (c) 1997 John Wiley & Sons, Inc.

P2-01-24: Triple-Negative Breast Cancer Emerges from the Luminal Progenitor Compartment

Background: Triple-negative breast cancers (TNBC) are defined as tumors that lack expression of estrogen receptor (ER), progesterone receptor (PgR), and human epidermal growth factor receptor type 2 (HER2). Majority of TNBC (approximately 80%) are basal-like breast cancers. The question of whether there is a specific, identifiable cell in the normal breast form which basal-like breast cancers arise is controversial. We evaluated the frequency and receptor status of ductal carcinoma in situ (DCIS) and ductal components associated with T1 invasive ductal carcinoma (IDC) to clarify the developmental pathway of TNBC.

Methods: From our institutional archives between April 2000 and April 2011, we retrieved 758 cases of DCIS and T1 invasive ductal carcinoma without prior operative treatment. Immunohistochemistry for ER, PgR and HER2 was performed on ductal components and invasive components. Statistical analysis was performed using Fisher Extract Test.

Results: The frequencies of triple-negative (TN) subtype at each size were not seen significant differences. Ductal components were seen in 51 (84%) TN-IDC cases. Within 51 cases, the ductal components were TN in 49 cases. The remaining 3 cases were positive for ER and PgR, but negative HER2.