Prognostic and biological significance of proliferation and HER2 expression in the luminal class of breast cancer

Clinicopathologic features of unexpectedly HER2 positive breast carcinomas: An institutional experience

Human epidermal growth factor receptor 2 (HER2) overexpression occurs in 15-20 % of all breast carcinomas. These tumors are usually high-grade which often correlates with reduced overall survival and increased rates of recurrence. In a retrospective review, we identified 19 cases of unexpectedly HER2 positive (by immunohistochemistry and/or fluorescence in-situ hybridization) invasive breast carcinomas on core needle biopsies from a registry at Northwestern Memorial Hospital. These cases included low-grade tumors, invasive lobular carcinomas, classic type, and invasive carcinomas with special subtype features. Twelve of the tumors were histologic grade 1 and 7 were histologic grade 2. One of the grade 1 tumors had tubular features (8 %), 1 had cribriform features (8 %), 2 had mucinous features (17 %), 2 were invasive lobular carcinomas, classic type (17 %), and the rest were invasive carcinoma, no special type (50 %). The histologic grade 2 tumors included 5 invasive lobular carcinomas, classic type (71 %) and 2 invasive ductal carcinomas with mucinous features (29 %). By immunohistochemistry, 13 (65 %) were HER2 score 3+, 7 were score 2+ (35 %), and reflex fluorescence in-situ hybridization (FISH) testing showed amplification in 6 cases, with 1 equivocal case amplified on excision. Despite the HER2 positive status in the selected cases, no unique morphologic features that would indicate aggressive behavior were identified. In clinical follow up, two patients were found to have recurrences, five had lymph node metastasis, and one had distant metastasis. None of the patients with recurrent disease were treated with trastuzumab, despite their positive HER2 results. These findings support that our population of HER2 positive carcinomas showed a similar rate of lymph node metastases and recurrence as poorly-differentiated tumors, supporting HER2 positivity as a poor prognostic indicator, irrespective of morphologic features. We recommend continuing to test all breast cancers, regardless of grade or special subtype features, to provide the most comprehensive treatment and prognostic information for both clinicians and patients.

Adjuvant Chemotherapy Guidance in Young Breast Cancer Patients With Luminal Subtypes and Stage pT1N0

BACKGROUND

This study evaluated whether young breast cancer patients (≤ 40 y of age) with luminal subtypes and stage pT1N0 can benefit from chemotherapy (CHT).

MATERIALS AND METHODS

This study included 688 patients aged ≤ 40 y with luminal subtypes and stage pT1N0 breast cancer. The overall survival and disease-free survival (DFS) rates in the whole cohort and subgroups were compared between patients receiving CHT followed by endocrinotherapy (ET) (CHT→ET group) and those receiving only ET (ET-alone group).

RESULTS

Univariate analysis identified that the tumors in the CHT→ET group were more aggressive than those in the ET-alone group. However, the overall survival and DFS rates did not differ significantly between the CHT→ET and ET-alone groups (P = 0.416 and 0.21, respectively), implying that a subgroup of patients could benefit from CHT. Subgroup analysis of DFS rates revealed that patients with human epidermal growth factor receptor 2 overexpression (P = 0.042), histological classification grade 3 (P = 0.030), progesterone receptor ≤ 20% (P = 0.033), and clinical stage T1c (P = 0.038) could benefit from CHT. Further analysis showed that these four risk factors combined predicted whether the patient could benefit from CHT.

CONCLUSIONS

Young patients with hormone receptor-positive and stage pT1N0 breast cancer may benefit from CHT only if they exhibit at least two of the following risk factors: progesterone receptor ≤ 20%, human epidermal growth factor receptor 2 overexpression, histological grading 3, or clinical stage T1c.

Targeting breast cancer cells with a CuInS2/ZnS quantum dot-labeled Ki-67 bioprobe

The aim of the present study was to develop a water-soluble biomarker for the detection of breast cancer using quantum dots (QDs) conjugated to Ki-67, a nuclear protein associated with the cell cycle. Ki-67 is also a marker of cell proliferation, with expression levels categorizing good and poor prognosis in invasive breast cancer. Ki-67 is a clinically used biomarker for breast cancer diagnosis, treatment and prognosis. Owing to the optical and chemical advantages of QDs, QD-based nanotechnology may aid the construction of a biomedical imaging platform for the study of cancer cell behavior. In the present study, a biomarker was prepared by employing the water-soluble CuInS₂/ZnS QDs conjugated to an anti-Ki-67 monoclonal antibody to detect Ki-67 expression in breast cancer. The QDs, which were hydrophobic and coated with octadecylamine, were encapsulated with an amphiphilic biocompatible centipede-like polymer, and then conjugated to anti-Ki-67 monoclonal antibodies (QD-Ki-67 probes). The QD-Ki-67 probes retained the original optical properties of the unadorned QDs and did not exhibit distinct toxic side effects in in vitro cytotoxicity experiments. Therefore, this CuInS₂/ZnS QD-labeled bioprobe, with a high quantum yield and low cytotoxicity, is a promising candidate for bioimaging and may be used as a cell label.

Prognostic stratification of oestrogen receptor-positive HER2-negative lymph node-negative class of breast cancer

AIMS

Multigene assay is recommended currently for prognostic stratification of the clinically indeterminate group of breast cancer (BC) patients defined as lymph node (LN)-negative, oestrogen receptor (ER)-positive, HER2-negative (LN^- /ER⁺ /HER2^- ) to determine the use of chemotherapy. However, this cohort, comprising approximately 40% of BC, is not a homogeneous group and shows variable outcome. This study aims to determine the prognostic value of routinely assessed variables, singly and in combination, in LN^- /ER⁺ /HER2^- BC patients.

METHODS AND RESULTS

A total of 830 LN^- /ER⁺ /HER2^- chemotherapy-naive BCs were investigated. The prognostic value of histological grade, tumour size, lymphovascular invasion (LVI), progesterone receptor (PgR) and Ki67 labelling index (Ki67LI) was assessed. In this series, only 25% of patients received hormone therapy. Median follow-up was 172 months. In the whole cohort, tumour grade, size, LVI, PgR and Ki67LI were correlated highly with outcome in a time-dependent manner. The outcome of this group varied widely from 97% (20% of cases) to 50% survival rate after 10-year follow-up using a combination of these markers. A prognostic index (Nottingham Px) incorporating grade, size, PgR and Ki67LI, was developed. The index can stratify the whole cohort robustly as well as the higher-risk subgroup (NPI score >3.4) into distinct prognostic classes.

CONCLUSION

Current routinely assessed variables can provide additional prognostic information in LN^- /ER⁺ /HER2^- BC. The proposed (Nottingham Px) index can stratify the BC clinically indeterminate group of patients into excellent and poor prognostic subgroups and can be used to identify reliably patients for systemic chemotherapy or further multigene prognostic testing. Performance of prognostic variables in these tumours is time-dependent, and should be considered in future studies.

Expression of CDK7, Cyclin H, and MAT1 Is Elevated in Breast Cancer and Is Prognostic in Estrogen Receptor-Positive Breast Cancer

PURPOSE

CDK-activating kinase (CAK) is required for the regulation of the cell cycle and is a trimeric complex consisting of cyclin-dependent kinase 7 (CDK7), Cyclin H, and the accessory protein, MAT1. CDK7 also plays a critical role in regulating transcription, primarily by phosphorylating RNA polymerase II, as well as transcription factors such as estrogen receptor-α (ER). Deregulation of cell cycle and transcriptional control are general features of tumor cells, highlighting the potential for the use of CDK7 inhibitors as novel cancer therapeutics.

EXPERIMENTAL DESIGN

mRNA and protein expression of CDK7 and its essential cofactors cyclin H and MAT1 were evaluated in breast cancer samples to determine if their levels are altered in cancer. Immunohistochemical staining of >900 breast cancers was used to determine the association with clinicopathologic features and patient outcome.

RESULTS

We show that expressions of CDK7, cyclin H, and MAT1 are all closely linked at the mRNA and protein level, and their expression is elevated in breast cancer compared with the normal breast tissue. Intriguingly, CDK7 expression was inversely proportional to tumor grade and size, and outcome analysis showed an association between CAK levels and better outcome. Moreover, CDK7 expression was positively associated with ER expression and in particular with phosphorylation of ER at serine 118, a site important for ER transcriptional activity.

CONCLUSIONS

Expressions of components of the CAK complex, CDK7, MAT1, and Cyclin H are elevated in breast cancer and correlate with ER. Like ER, CDK7 expression is inversely proportional to poor prognostic factors and survival. Clin Cancer Res; 22(23); 5929-38. ©2016 AACR.

SERPINA1 is a direct estrogen receptor target gene and a predictor of survival in breast cancer patients

Of all breast cancer patients, about 70% are ER+ and 10% are ER+/HER2+. The ER+/HER2+ patients have a worse outcome compared to ER+/HER2- patients. Currently there is a lack of effective prognosis biomarkers for the prediction of outcome in ER+/HER2+ patients. Genome-wide differences in ER binding between the endocrine-responsive and endocrine-resistant cells were discovered using ChIP-seq, and combined with gene expression microarray data to identify direct ER target genes. These genes were correlated to survival outcome using publicly available breast cancer patient cohorts. We found the expression of the gene SERPINA1 to have a significant predictive value for the overall survival (OS) of ER+ patients in the TCGA cohort, and validated this finding in the Curtis cohort. SERPINA1 also has a significant predictive value for the OS of ER+/HER2+ patients in the TCGA cohort, with validation in the Bild cohort. The expression of SERPINA1 can be suppressed by fulvestrant and HER2 siRNA. Our results indicate that ER is constitutively activated, resulting in an E2-independent ER binding to the SERPINA1 gene and upregulation of SERPINA1 expression. Importantly, results of survival correlation suggests that high expression of SERPINA1 could be predictive for a better clinical outcome of ER+ and ER+/HER2+ patients.

Protective autophagy promotes the resistance of HER2-positive breast cancer cells to lapatinib

Lapatinib, a tyrosine kinase inhibitor of HER2/EGFR, can inhibit the proliferation of HER2-positive breast cancer cells. Additionally, the combination of lapatinib and chemotherapy can markedly prolong patient survival time. However, the clinical therapeutic effect of lapatinib is severely limited by drug resistance. We previously found that brief treatment with lapatinib induced both apoptosis and autophagy in HER2-positive breast cancer cells. Additionally, the apoptosis induced by lapatinib was dependent on autophagy. In our current study, however, we used extended treatment of HER2-positive breast cancer cells with lapatinib to confirm the presence of protective autophagy in the previously established lapatinib-resistant cells. Specifically, we found that inhibition of autophagy could reduce the proliferation, DNA synthesis, and colony-forming capacity of resistant cells. Thus, autophagy is a potential novel therapeutic target for reversing lapatinib resistance of HER2-positive breast cancer cells. Our data provide clear, novel evidence of both anti-apoptotic and pro-apoptotic functions of autophagy in breast cancer during lapatinib treatment.

Quantum dot-based multispectral fluorescent imaging to quantitatively study co-expressions of Ki67 and HER2 in breast cancer

Both Ki67 and HER2 are key prognostic molecules for invasive breast cancer (BC), but the individual relative impacts on prognosis of these molecules are not known. This study was aimed at establishing a quantum dot (QD)-based double-color in-situ quantitative imaging technique to study the co-expressions of Ki67 and HER2, and delineate the individual impacts of these molecules on prognosis. The QD-based fluorescent immunostaining technique could simultaneously image the co-expressions of Ki67 and HER2 in BC specimens, with the former stained as clear red fluorescence in cancer cell nucleus, and the latter as bright green fluorescence on cancer cell membrane. Both Ki67 and HER2 expressions were significantly correlated with 8-year disease free survival (8-DFS) (P<0.05). However, the two molecules had different weights in terms of negative impacts on clinical prognosis. The median 8-DFS was statistically significantly shorter in High-Ki67 High-HER2 subgroup than Low-Ki67 High-HER2 subgroup (11.7 vs. 60.1months, P<0.05), shorter in High-Ki67 Low-HER2 subgroup than Low-Ki67 Low-HER2 subgroup (16.4 vs. 96.0months, P<0.01), shorter in High-Ki67 High-HER2 subgroup than Low-Ki67 Low-HER2 subgroup (11.7 vs. 96.0months, P<0.01), but there were no statistically significant differences in median 8-DFS between High-Ki67 Low-HER2 subgroup and High-Ki67 High-HER2 subgroup (11.7 vs. 16.4months, P=0.586). The hazard ratio (HR) of Ki67 negative impact on 8-DFS was about 3 fold of that of HER2 (HR 4.493 vs. 1.481). This study demonstrated that QD-based fluorescent imaging technique could help the quantitative study on the co-expressions of Ki67 and HER2 in BC, and Ki67 has a greater negative impact on BC prognosis than HER2.

Prognosis of lymph node-negative breast cancer: Association with clinicopathological factors and tumor associated gene expression

The aim of the present study was to investigate the association between the prognosis of lymph node-negative breast cancer patients and clinicopathological factors, as well as the association between tumor-associated gene expression and prognosis. Clinical data and survival information was collected for 341 patients with lymph node-negative breast cancer, admitted to the Cancer Hospital of the Chinese Academy of Medical Sciences (Beijing, China) from 1995 to 1999. Kaplan-Meier survival analysis and Log-rank tests were used to evaluate the association of clinical parameters and prognosis. In addition, the gene expression of HER2, TOP2A and CCND1 in patients with good [disease-free survival (DFS), ≥5 years] and poor (DFS, <5 years) prognoses was analyzed. The clinicopathological factors of the 341 lymph node-negative breast cancer patients were determined. The 5-year DFS and overall survival rate (OS) in patients >35 years old was higher as compared with those of patients under the age of 35. Tumor size significantly affected the 5-year DFS. Patients with smaller tumors (≤2 cm) had a significantly higher DFS rate as compared with patients with larger tumors (>2 cm). Estrogen receptor (ER)-positive patients had a significantly higher 5-year DFS and OS rate as compared with ER-negative patients. By contrast, there were no significant differences in the 5-year DFS and OS rates between progesterone receptor-positive and -negative patients. The 5-year DFS and OS rates were significantly higher in patients treated with adjuvant hormone therapy, as compared with patients without hormone therapy. The expression of HER2 protein was higher in patients with a poor prognosis as compared with those with a good prognosis; however, there were no differences in the protein expression of CCND1 and TOP2A between patients with a good and poor prognosis. The results of quantitative polymerase chain reaction showed that the gene expression of HER2 and CCND1 was higher in patients with a poor prognosis as compared with that in patients with a good prognosis. TOP2A gene expression was not significantly different between patients with a poor and good prognosis. The age at diagnosis, tumor size, ER status and hormone therapy were associated with prognosis in patients with lymph node-negative breast cancer. The molecular biomarker, HER2, but not CCND1 or TOP2A, may be a critical factor for predicting prognosis.