Association between c-myc amplification and pathological complete response to neoadjuvant chemotherapy in breast cancer

Distinct clinicopathological characteristics, genomic alteration and prognosis in breast cancer with concurrent TP53 mutation and MYC amplification

BACKGROUND

Both TP53 mutation and MYC amplification indicate poor outcomes in breast cancer (BC), but the clinical values of concurrent TP53 and MYC alterations have not been well-characterized.

METHODS

A total of 494 BC patients diagnosed at Guangdong Provincial People's Hospital (GDPH) were retrospectively analyzed. Genomic alterations were determined using next-generation sequencing. Survival analysis was applied to assess the effects of genetic alterations on relapse-free survival. The prognosis was verified based on 1405 patients from METABRIC cohort. Additionally, we used logistic regression to identify the factors associated with pathological complete response (pCR) after neoadjuvant chemotherapy.

RESULTS

In GDPH cohort, patients with TP53/MYC co-alteration exhibited higher grade and stage, more positive HER2 status and higher Ki67 levels, but less luminal A subtypes. They also had more mutations in genes involved in ERBB and TGF-β signaling pathways, as well as exclusive FANCG/CDKN2B/QKI copy number amplifications and SUFU/HIST3H3/ERCC4/JUN/BCR mutations. Concurrent TP53 and MYC alterations independently increased hazards of relapse (HR, 5.425; 95% CI: 2.019-14.579; p < 0.001). They maintained independent significance for relapse-free (HR, 1.310; 95% CI: 1.012-1.697; p = 0.041) and overall survival (HR, 1.373; 95% CI: 1.093-1.725; p = 0.006) in METABRIC cohort. Among the 81 patients receiving chemotherapy, TP53 mutation (OR, 5.750; 95% CI: 1.553-25.776; p = 0.013) and earlier stage (OR, 0.275; 95% CI 0.088-0.788; p = 0.020) were associated with pCR, while the co-alteration did not serve as an independent predictor (p = 0.199).

CONCLUSIONS

TP53/MYC co-alteration was associated with distinct clinicopathological and genomic features. They also conferred unfavorable prognosis in BC patients, and did not improve pCR after neoadjuvant chemotherapy.

Integrated multi-omics profiling of high-grade estrogen receptor-positive, HER2-negative breast cancer

Estrogen receptor‐positive and human epidermal growth factor receptor 2‐negative (ER⁺HER2⁻) breast cancer accounts for ~ 60–70% of all cases of invasive breast carcinoma. High‐grade ER⁺HER2⁻ tumors respond poorly to endocrine therapy. In this study, we systematically analyzed clinical and multi‐omics data to find potential strategies for personalized therapy of patients with high‐grade ER⁺HER2⁻ disease. Six different cohorts were analyzed, for which multi‐omics data were available. Grade III ER⁺HER2⁻ cases harbored higher proportions of large tumor size (> 5 cm), lymph node metastasis, chemotherapy use, and luminal B subtypes defined by PAM50, as compared with grade I/II tumors. DNA methylation (HM450) data and methylation‐specific PCR indicated that the cg18629132 locus in the MKI67 promoter was hypermethylated in grade I/II cases and normal tissue, but hypomethylated in grade III cases or triple‐negative breast cancer, resulting in higher expression of MKI67. Mutations in ESR1 and TP53 were detected in post‐endocrine treatment metastatic samples at a higher rate than in treatment‐naive tumors in grade III cases. We identified 42 and 20 focal copy number events in nonmetastatic and metastatic high‐grade ER⁺HER2⁻ cases, respectively, with either MYC or MDM2 amplification representing an independent prognostic event in grade III cases. Transcriptional profiling within grade III tumors highlighted ER signaling downregulation and upregulation of immune‐related pathways in non‐luminal‐like tumors defined by PAM50. Recursive partitioning analysis was employed to construct a decision tree of an endocrine‐resistant subgroup (GATA3‐negative and AGR‐negative) of two genes that was validated by immunohistochemistry in a Chinese cohort. All together, these data suggest that grade III ER⁺HER2⁻ tumors have distinct clinical and molecular characteristics compared with low‐grade tumors, particularly in cases with non‐luminal‐like biology. Due to the dismal prognosis in this group, clinical trials are warranted to test the efficacy of potential novel therapies.

Tumor Suppressor Effect of RBMS3 in Breast Cancer

Background:

RBMS3 (RNA-binding motif, single-stranded-intervacting protein 3) acts as a tumor-suppressive gene in a number of human cancers, however, its role in breast cancer is not fully understood. This study aimed to investigate the expression and clinicopathological significance of RBMS3 in breast cancer.

Methods:

A total of 998 breast cancer tissue samples in The Cancer Genome Atlas (TCGA) database with survival outcomes were divided into high RBMS3 expression and low expression groups using the median as the cutoff. Clinicopathological characteristics and prognosis were compared between the 2 groups.

Results:

TCGA showed that RBMS3 mRNA was downregulated in breast cancer tissues, and RBMS3 downregulation was correlated with poor prognosis. Immunohistochemistry staining of 127 paraffin-embedded breast cancer tissues showed that RBMS3 protein was localized in the cytoplasm and nucleus; however, nuclear staining was present in 90.0% of normal breast tissues but only 28.3% of breast cancer tissues. Decreased RBMS3 protein expression was significantly correlated with estrogen receptor (ER)-negative status and death at final follow-up. Patients with lower RBMS3 protein expression had substantially shorter survival than those with higher RBMS3 expression. Univariate and multivariate analysis indicated that the combination of RBMS3 expression and ER status (a variable designated as “cofactor”) was an independent prognostic factor in patients with breast cancer (hazard ratio [HR] = 0.420, 95% confidence interval [CI]: 0.223-0.791, P = 0.007).

Conclusion:

RBMS3 downregulation was correlated with poor prognosis in breast cancer patients, and the combination of RBMS3 expression and ER status was an independent prognostic factor.

The modern views of the clinical, morphological and molecular biological predictors of breast cancer sensitivity to chemotherapy

In the treatment of breast cancer, the neoadjuvant chemotherapy is vitally important and the evaluation of its effectiveness is crucial for determining the further therapy treatment, as well as the prognosis of the disease. This review provides current data of the physical, instrumental, morphological, molecular biology and genetics analysis used for the estimation of the neoadjuvant treatment effectiveness. Thus, review discusses the data concerning association of the disease peculiarities with the efficient therapeutic response to neoadjuvant chemotherapy including characteristics of patients (age, status of regional lymph nodes, presence of the lymphovascular invasion) and tumors (size, histological type, degree of differentiation, severity of the lymphoid tumor infiltration, molecular biological and genetic peculiarities). Particular attention is paid to such a promising predictive marker of the breast cancer response to chemotherapy as the level of tissue hypoxia. This section discusses the currently known mechanisms that might enable the effect of tissue hypoxia on the sensitivity of the tumor to drug treatment. The prospects for the use of a comprehensive analysis of predictive markers of the effectiveness of chemotherapeutic treatment are discussed.

Myc and the Replicative CMG Helicase: The Creation and Destruction of Cancer: Myc Over-Activation of CMG Helicases Drives Tumorigenesis and Creates a Vulnerability in CMGs for Therapeutic Intervention

Myc-driven tumorigenesis involves a non-transcriptional role for Myc in over-activating replicative Cdc45-MCM-GINS (CMG) helicases. Excessive stimulation of CMG helicases by Myc mismanages CMG function by diminishing the number of reserve CMGs necessary for fidelity of DNA replication and recovery from replicative stresses. One potential outcome of these events is the creation of DNA damage that alters genomic structure/function, thereby acting as a driver for tumorigenesis and tumor heterogeneity. Intriguingly, another potential outcome of this Myc-induced CMG helicase over-activation is the creation of a vulnerability in cancer whereby tumor cells specifically lack enough unused reserve CMG helicases to recover from fork-stalling drugs commonly used in chemotherapy. This review provides molecular and clinical support for this provocative hypothesis that excessive activation of CMG helicases by Myc may not only drive tumorigenesis, but also confer an exploitable "reserve CMG helicase vulnerability" that supports developing innovative CMG-focused therapeutic approaches for cancer management.

Clonal diversity of MYC amplification evaluated by fluorescent in situ hybridisation and digital droplet polymerase chain reaction in oesophagogastric cancer: Results from a prospective clinical trial screening programme

INTRODUCTION

The MYC proto-oncogene is among the most commonly dysregulated genes in human cancers. We report screening data from the iMYC trial, an ongoing phase II study assessing ibrutinib monotherapy in advanced pretreated MYC- and/or HER2-amplified oesophagogastric cancer, representing the first attempt to prospectively identify MYC amplifications in this tumour type for the purposes of therapeutic targeting.

METHODS

Screening utilising a fluorescent in situ hybridisation (FISH) assay for assessment of tumour MYC amplification has been instituted. An experimental digital droplet polymerase chain reaction (ddPCR) assay to assess MYC amplification in both tumour and circulating-tumour (ct)DNA has been developed and investigated.

RESULTS

One hundred thirty-five archival tumour specimens have undergone successful FISH analysis with 23% displaying evidence of MYC amplification. Intertumour heterogeneity was observed, with the percentage of cancer cells harbouring MYC amplification ranging widely between samples (median 51%, range 11-94%). Intratumoural clonal diversity of MYC amplification was also observed, with a significant degree of variance in amplification ratios (Bartlett's test for equal variance p < 0.001), and an association between greater variance in MYC amplification and improved outcome with prior first-line chemotherapy. ddPCR was most accurate in quantifying MYC amplification in tumour-derived DNA from cases with a high proportion (>70%) of amplified cells within the tumour specimen but was not reliable in samples containing a low proportion of amplified cells or in ctDNA.

CONCLUSIONS

Our results illustrate the utility of FISH to assess MYC amplification prospectively for a biomarker-selected trial by providing reliable and reproducible results in real time, with a high degree of heterogeneity of MYC amplification observed. We show that ddPCR can potentially detect high-level MYC amplifications in tumour tissue.

Somatic alterations of TP53, ERBB2, PIK3CA and CCND1 are associated with chemosensitivity for breast cancers

The correlation of genetic alterations with response to neoadjuvant chemotherapy (NAC) has not been fully revealed. In this study, we enrolled 247 breast cancer patients receiving anthracycline‐taxane‐based NAC treatment. A next generation sequencing (NGS) panel containing 36 hotspot breast cancer‐related genes was used in this study. Two different standards for the extent of pathologic complete response (pCR), ypT0/isypN0 and ypT0/is, were used as indicators for NAC treatment. TP53 mutation (n = 149, 60.3%), PIK3CA mutation (n = 109, 44.1%) and MYC amplification (n = 95, 38.5%) were frequently detected in enrolled cases. TP53 mutation (P = 0.019 for ypT0/isypN0 and P = 0.003 for ypT0/is) and ERBB2 amplification (P < 0.001 for both ypT0/isypN0 and ypT0/is) were related to higher pCR rates. PIK3CA mutation (P = 0.040 for ypT0/isypN0) and CCND2 amplification (P = 0.042 for ypT0/is) showed reduced sensitivity to NAC. Patients with MAPK pathway alteration had low pCR rates (P = 0.043 for ypT0/is). Patients with TP53 mutation (−) PIK3CA mutation (−) ERBB2 amplification (+) CCND1 amplification (−), TP53 mutation (+) PIK3CA mutation (−) ERBB2 amplification (+) CCND1 amplification (−) or TP53 mutation (+) PIK3CA mutation (+) ERBB2 amplification (+) CCND1 amplification (−)had significantly higher pCR rates (P < 0.05 for ypT0/isypN0 and ypT0/is) than wild type genotype tumors. Some cancer genetic alterations as well as pathway alterations were associated with chemosensitivity to NAC treatment. Our study may shed light on the molecular characteristics of breast cancer for prediction of NAC expectations when breast cancer is first diagnosed by biopsy.

MYC amplification in subtypes of breast cancers in African American women

Background

MYC overexpression is associated with poor prognosis in breast tumors (BCa). The objective of this study was to determine the prevalence of MYC amplification and associated markers in BCa tumors from African American (AA) women and determine the associations between MYC amplification and clinico-pathological characteristics.

Methods

We analyzed 70 cases of well characterized archival breast ductal carcinoma specimens from AA women for MYC oncogene amplification. Utilizing immune histochemical analysis estrogen receptor (ER), progesterone receptor (PR), and (HER2/neu), were assessed. Cases were Luminal A (ER or PR+, Ki-67 < 14%), Luminal B (ER or PR+, Ki-67 = > 14% or ER or PR+ HER2+), HER2 (ER-, PR-, HER2+), and Triple Negative (ER-, PR-, HER2-) with basal-like phenotype. The relationship between MYC amplification and prognostic clinico-pathological characteristics was determined using chi square and logistic regression modeling.

Results

Sixty-five (97%) of the tumors showed MYC gene amplification (MYC: CEP8 > 1). Statistically significant associations were found between MYC amplification and HER2-amplified BCa, and Luminal B subtypes of BCa (p < 0.0001), stage (p < 0.001), metastasis (p < 0.001), and positive lymph node status (p = 0.039). MYC amplification was associated with HER2 status (p = 0.01) and tumor size (p = 0.01). High MYC amplification was seen in grade III carcinomas (MYC: CEP8 = 2.42), pre-menopausal women (MYC: CEP8 = 2.49), PR-negative status (MYC: CEP8 = 2.42), and ER-positive status (MYC: CEP8 = 2.4).

Conclusions

HER2 positive BCas in AA women are likely to exhibit MYC amplification. High amplification ratios suggest that MYC drives HER2 amplification, especially in HER2 positive, Luminal B, and subtypes of BCa.

c-Myc is regulated by HIF-2α in chronic hypoxia and influences sensitivity to 5-FU in colon cancer

Colorectal cancers (CRCs) invariably become hypoxic as they enlarge, and this places unique metabolic demands upon the tumor cells. Hypoxic stress can enhance the invasiveness of cancer cells and induce chemoresistance. c-Myc, an oncogene regulated by hypoxia inducible factors (HIFs), plays a critical role in cell proliferation and metabolism. However, the interplay between c-Myc and HIFs and its clinical significance in hypoxic adaptation in CRCs are unknown. We demonstrate that c-Myc mRNA and protein levels in colon cancer cells are induced within 2 h of hypoxic stress (1% O₂) but are then significantly downregulated when exposed to prolonged hypoxia. In chronic hypoxia (over 8 h at 1% O₂), HIF-2α but not HIF-1α gradually accumulated in colon cancer cells. Knockdown of HIF-2α increased levels of c-Myc and its downstream target cyclinD1 in chronic hypoxia, indicating that HIF-2α may function to downregulate c-Myc. Chronic hypoxia suppressed the expression of cyclinD1, CDK4, and CDK6, inducing G1 phase block and 5-flurouracil (5-FU) chemoresistance. Overexpression of c-Myc reversed the inhibition of cyclinD1, CDK4, and CDK6, which accelerated the G1/S phase transition under hypoxia and enhanced sensitivity to 5-FU. In contrast, knockdown of c-Myc impaired 5-FU chemosensitivity in colon cancer cells. In summary, HIF-2α plays an important role in regulating the expression of c-Myc in chronic hypoxia, and consequently controls the sensitivity of colon cancer cells to 5-FU treatment in this environment.

MYC Amplification as a Predictive Factor of Complete Pathologic Response to Docetaxel-based Neoadjuvant Chemotherapy for Breast Cancer

BACKGROUND

Neoadjuvant chemotherapy is a standard treatment for stage II and III breast cancer. The identification of biomarkers that may help in the prediction of response to neoadjuvant therapies is necessary for a more precise definition of the best drug or drug combination to induce a better response.

MATERIAL AND METHODS

We assessed the role of Ki67, hormone receptors expression, HER2, MYC genes and their protein status, and KRAS codon 12 mutations as predictor factors of pathologic response to anthracycline-cyclophosphamide (AC) followed by taxane docetaxel (T) neoadjuvant chemotherapy (AC+T regimen) in 51 patients with invasive ductal breast cancer.

RESULTS

After neoadjuvant chemotherapy, 82.4% of patients showed pathologic partial response, with only 9.8% showing pathologic complete response. In multivariate analysis, MYC immunoreactivity and high MYC gain defined as MYC/nucleus ≥ 5 were significant predictor factors for pathologic partial response. Using the receiver operating characteristic curve analysis, the ratio of 2.5 MYC/CEP8 (sensitivity of 80% and specificity of 89.1%) or 7 MYC/nuclei copies (sensitivity of 80% and specificity of 73.9%) as the best cutoff in predicting a pathologic complete response was identified. Thus, MYC may have a role in chemosensitivity to AC and/or docetaxel drugs. Additionally, MYC amplification may be a predictor factor of pathologic response to the AC+T regimen in patients with breast cancer. Moreover, patients with an increased number of MYC copies showed pathologic complete response to this neoadjuvant treatment more frequently.

CONCLUSION

The analysis of MYC amplification may help in the identification of patients that may have a better response to AC+T treatment.

A microscopic landscape of the invasive breast cancer genome

Histologic grade is one of the most important microscopic features used to predict the prognosis of invasive breast cancer and may serve as a marker for studying cancer driving genomic abnormalities in vivo. We analyzed whole genome sequencing data from 680 cases of TCGA invasive ductal carcinomas of the breast and correlated them to corresponding pathology information. Ten genetic abnormalities were found to be statistically associated with histologic grade, including three most prevalent cancer driver events, TP53 and PIK3CA mutations and MYC amplification. A distinct genetic interaction among these genomic abnormalities was revealed as measured by the histologic grading score. While TP53 mutation and MYC amplification were synergistic in promoting tumor progression, PIK3CA mutation was found to have alleviated the oncogenic effect of either the TP53 mutation or MYC amplification, and was associated with a significant reduction in mitotic activity in TP53 mutated and/or MYC amplified breast cancer. Furthermore, we discovered that different types of genetic abnormalities (mutation versus amplification) within the same cancer driver gene (PIK3CA or GATA3) were associated with opposite histologic changes in invasive breast cancer. In conclusion, our study suggests that histologic grade may serve as a biomarker to define cancer driving genetic events in vivo.

MYC is expressed in the stromal and epithelial cells of primary breast carcinoma and paired nodal metastases

The MYC oncogene is directly involved in the proliferation, metabolism, progression and distant metastasis of breast cancer. Since metastatic spread to the lymph nodes is often the first indication of propensity for metastatic dissemination, the MYC status in nodal disease may represent a decision-making variable. However, the analysis of MYC expression in stromal cells, namely cancer-associated fibroblasts (CAFs), which are known to play a critical role in cancer progression, remains poorly reported. The aim of this study was to determine the expression of MYC and other markers, including estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), p53, Ki67, epidermal growth factor receptor (EGFR), phosphorylated AKT (p-AKT) and phospho-mammalian target of rapamycin (p-mTOR) by immunohistochemistry in representative samples from 80 patients with ductal infiltrative breast cancer and 43 paired compromised axillary lymph nodes allocated in tissue microarrays (TMAs). The epithelial and stromal components of primary tumors and respective lymph node metastases were separately analyzed. MYC expression (cytoplasmic and nuclear) was a frequent event in the epithelial and stromal components of the primary tumors. The epithelial cells in the nodal metastases exhibited a trend for decreased MYC expression compared to that in the primary tumors (P=0.08) but retained the original status of the primary tumors for all other markers. The stromal cells were uniformly negative for ER, PR, HER2, p53, Ki67 and EGFR. Comparison of the stromas of primary tumors and respective lymph node metastases revealed a reduced frequency of nuclear MYC in 15% of the cases (P=0.003), whereas p-mTOR followed a similar trend (P=0.09). Analyses of the possible correlations among markers revealed that epithelial nuclear MYC was associated with p53 (P=0.048). This is an original study demonstrating a significant proportion of MYC expression (nuclear or cytoplasmic), as well p-mTOR and p-AKT expression, in the epithelial and stromal components of either the primary tumor or the nodal metastases. CAFs expressing MYC may establish an angiogenic microenvironment supporting cancer survival and facilitating colonization at the nodal metastatic site.

Combined analysis of copy number alterations by single-nucleotide polymorphism array and MYC status in non-metastatic breast cancer patients: comparison according to the circulating tumor cell status

Recent technological advances have made it possible to detect circulating tumor cells (CTCs) as a prognostic marker in operable breast cancer patients. Whether the presence of CTCs in cancer patients correlates with molecular alterations in the primary tumor has not been widely explored. We identified 14 primary breast cancer specimens with known CTC status, in order to evaluate the presence of differential genetic aberrations by using SNP array assay. There was a global increase of altered genome, CNA, and copy-neutral loss of heterozygosity (cn-LOH) observed in the CTC-positive (CTC(+)) versus CTC-negative (CTC(-)) cases. As the preliminary results showed a higher proportion of copy number alteration (CNA) at 8q24 (MYC loci) and the available evidence supporting the role of MYC in the processes cancer metastases is conflicting, MYC status was determined in tissue microarray sections in a larger series of patients (n = 49) with known CTC status using FISH. MYC was altered in 62% (16/26) CTC(+) patients and in 43% (6/14) CTC(-) patients (p = 0.25). Based on the observation in our study, future studies involving a larger number of patients should be performed in order to definitively define if this correlation exists.

Free circulating tumor DNA as a diagnostic marker for breast cancer

BACKGROUND

Cell-free DNA (cfDNA) in the plasma of patients with both malignant and benign breast lesions was analyzed to determine whether the findings may have diagnostic and prognostic implications and to analyze the association between the levels of cfDNA and prognostic parameters.

METHODS

Plasma samples were obtained from 99 subjects; 42 with breast cancer (BC), 30 with benign breast lesions, and 27 healthy women as normal controls. Circulatory cfDNA was extracted from the plasma samples and quantified using a real-time quantitative PCR method. Immunohistochemistry was done on formalin-fixed paraffin-embedded sections to evaluate the status of hormonal receptors (estrogen receptor [ER] and progesterone receptor [PR]), and the protein expression of both Her2/neu and Topoisomerase IIα.

RESULTS

The level of cfDNA in the BC group was significantly higher than in the benign lesions and control groups. cfDNA level was associated with malignant tumor size, lymph node involvement, stage, and grade as well as Her2/neu and Topoisomerase IIα expression, while it was not associated with ER or PR status.

CONCLUSIONS

The present study suggests that the level of cfDNA can be easily quantified using plasma samples. Thus, level of plasma cfDNA might constitute an important noninvasive diagnostic and prognostic valuable tool in cancer breast patients' management.

8q24 amplification is associated with Myc expression and prostate cancer progression and is an independent predictor of recurrence after radical prostatectomy

Genomic alterations affecting the 8q24 region are frequent in prostate cancer. Together with the oncogene MYC, other genes located in the surrounding of the amplified region could also be candidate targets. Tissue microarrays were constructed with prostate cancer tissues from (1) a case-control population of patients treated by radical prostatectomy (n = 242; 121 cases with biochemical relapse matched with 121 cancers with identical clinicopathologic features but without relapse), (2) castration-resistant disease (n = 55), and (3) metastatic cancers (n = 28). Fluorescence in situ hybridization and immunohistochemistry were used on tissue microarrays and slides to analyze, respectively, the amplification status of 8q24 and protein expression of genes located at 8q24. Amplification at the MYC locus was observed in 29% of cases and was closely associated with both disease progression (from 15% in pT2 tumors to 53% in metastasis; P = .001), and Gleason score (from <3% in Gleason 6 tumors to 66% in Gleason 8 and more tumors; P < .0001). The expression of genes located at 8q24 did not correlated with the amplification status, except for the Myc protein (P = .002). MYC amplification status but not Myc protein expression was significantly predictive of biochemical recurrence after prostatectomy, together with the proliferation marker Ki-67 and independently from known prognostic factors, including TNM stage and Gleason score. The MYC amplification status could constitute a useful prognostic tool for patients treated by radical prostatectomy, particularly for those with d'Amico intermediate risk, whose clinical behavior is currently difficult to predict.

Prognostic and predictive significance of MYC and KRAS alterations in breast cancer from women treated with neoadjuvant chemotherapy

Breast cancer is a complex disease, with heterogeneous clinical evolution. Several analyses have been performed to identify the risk factors for breast cancer progression and the patients who respond best to a specific treatment. We aimed to evaluate whether the hormone receptor expression, HER2 and MYC genes and their protein status, and KRAS codon 12 mutations may be prognostic or predictive biomarkers of breast cancer. Protein, gene and mutation status were concomitantly evaluated in 116 breast tumors from women who underwent neoadjuvant chemotherapy with doxorubicin plus cyclophosphamide. We observed that MYC expression was associated with luminal B and HER2 overexpression phenotypes compared to luminal A (p<0.05). The presence of MYC duplication or polysomy 8, as well as KRAS mutation, were also associated with the HER2 overexpression subtype (p<0.05). MYC expression and MYC gain were more frequently observed in early-onset compared to late-onset tumors (p<0.05). KRAS mutation was a risk factor of grade 3 tumors (p<0.05). A multivariate logistic regression demonstrated that MYC amplification defined as MYC/nucleus ratio of ≥2.5 was a protective factor for chemotherapy resistance. On the other hand, age and grade 2 tumors were a risk factor. Additionally, luminal B, HER2 overexpression, and triple-negative tumors presented increased odds of being resistant to chemotherapy relative to luminal A tumors. Thus, breast tumors with KRAS codon 12 mutations seem to present a worse prognosis. Additionally, MYC amplification may help in the identification of tumors that are sensitive to doxorubicin plus cyclophosphamide treatment. If confirmed in a large set of samples, these markers may be useful for clinical stratification and prognosis.

Biomarker analysis of neoadjuvant doxorubicin/cyclophosphamide followed by ixabepilone or Paclitaxel in early-stage breast cancer

PURPOSE

Predictive biomarkers offer the potential to improve the benefit:risk ratio of a therapeutic agent. Ixabepilone achieves comparable pathologic complete response (pCR) rates to other active drugs in the neoadjuvant setting. This phase II trial was designed to investigate potential biomarkers that differentiate response to this agent.

EXPERIMENTAL DESIGN

Women with untreated, histologically confirmed primary invasive breast adenocarcinoma received neoadjuvant doxorubicin/cyclophosphamide, followed by 1:1 randomization to ixabepilone (n = 148) or paclitaxel (n = 147). Rates of pCR were compared between treatment arms based on predefined biomarker sets: TUBB3, TACC3, and CAPG gene expression, a 20- and 26-gene expression model, MDR1 protein expression, and other potential markers of sensitivity. βIII-tubulin protein expression is reported separately but is referred to here for completeness. All patients underwent a core needle biopsy of the primary cancer for molecular marker analysis before chemotherapy. Gene expression profiling data were used for molecular subtyping.

RESULTS

There was no significant difference in the rate of pCR in both treatment arms in βIII-tubulin-positive patients. Higher pCR rates were observed among βIII-tubulin-positive patients than in βIII-tubulin-negative patients. Furthermore, no correlation was evident between TUBB3, TACC3, and CAPG gene expression, MDR1 protein expression, multi-gene expression models, and the efficacy of ixabepilone or paclitaxel, even within the estrogen receptor-negative subset.

CONCLUSION

These results indicate that βIII-tubulin protein and mRNA expression, MDR1 protein expression, TACC3 and CAPG gene expression, and multigene expression models (20- and 26-gene) are not predictive markers for differentiating treatment benefit between ixabepilone and paclitaxel in early-stage breast cancer.

Vaccination with embryonic stem cells generates effective antitumor immunity against ovarian cancer

To date, only a few studies have suggested that human embryonic stem cells (hESCs) might effectively immunize against colon and lung cancer. The purpose of this study was to investigate the therapeutic potential of hESCs as a vaccine to induce widespread antitumor effects in different animal models and various types of cancer. C57BL/6 mice with ID8 ovarian cancer cell and Fischer 344 rats with NuTu-19 ovarian cancer cell models were used. Fifty-four mice were divided into six groups with nine mice in each group. Each mouse was immunized with pre-inactivated hESCs (H9) or mouse embryonic stem cells (mESCs; IVP-ES1) or ID8 or phosphate-buffered saline (PBS). Twenty-four rats were divided into four groups with six rats in each group, each rat immunized with pre-inactivated hESCs (H9) or NuTu-19 or PBS. After the vaccination, each mouse was challenged with live ID8 cells subcutaneously, and each rat was challenged with live NuTu-19 cells intraperitoneally. We discovered that vaccination of mice with the hESC line H9 and the mESC line IVP-ES1 generated consistent cellular and humoral immune responses against ID8 ovarian cancer. H9 and IVP-ES1 vaccinated mice obtained antitumor immune protection, and H9 vaccinated rats had the longest survival time and least distant metastases. No evidence of side-effects was observed. We also compared the immunogenicity against ovarian cancer between the hESC line, H9, and the mESC line, IVP-ES1, that derived from the inner cell mass in different species. We found that there were no significant differences between them. Furthermore, immunohistochemical staining revealed that several oncogenes and tumor suppressor genes, such as HER-2, C-myc, p53, and nm23, were expressed in H9, many of which were also shared by ovarian cancer. hESC vaccines can induce antitumor effects in two animal models and in ovarian cancer, indicating that the activity of the vaccine is universal, and, more importantly, it is safe.

Prognostic relevance of c-Myc and BMI1 expression in patients with glioblastoma

Although the c-Myc oncogene is frequently deregulated in human cancer, its involvement in the pathogenesis of glioblastoma is not clear. We conducted immunohistochemical analysis of the expression of c-Myc, polycomb ring finger oncogene (BMI1), and acetylation of the lysine 9 (H3K9Ac) of histone 3 in 48 patients with glioblastoma who underwent surgery followed by radiotherapy and temozolomide treatment. The expression of c-Myc, BMI1, and H3K9ac was correlated with clinical characteristics and outcome. We found that overexpression of c-Myc was significantly associated with that of BMI1 (P = .009), and that patients who harbored glioblastomas overexpressing c-Myc and BMI1 showed significantly longer overall survival (P < .0001 and P = .0009, respectively). Our results provide the first evidence of the prognostic value of c-Myc and associated genes in patients with glioblastoma. The favorable effect of c-Myc and BMI1 expression on survival is likely mediated by the sensitization of cancer cells to radiotherapy and temozolomide through the activation of apoptotic pathways.

C-myc as a predictive marker for chemotherapy in metastatic breast cancer

C-myc is considered to have an important role in cancerogenesis and tumor progression. The aim of this study was to evaluate a possible significance of c-myc amplification as a clinically useful prognostic/predictive parameter in metastatic breast cancer (MBC). Eighty-seven MBC patients with known clinicopathological parameters were included in the study, at the time of diagnosis of metastatic disease. In metastatic setting, 52% of patients received CMF, 34% received FAC, and 32% received hormonal therapy (tamoxifen). C-myc amplification was analyzed by chromogenic in situ hybridization, according to the manufacturer's instructions. C-myc amplification was detected in 26% cases and showed a strong correlation with ER status, stage of disease (initial) and existence of distance metastasis. There was no statistically significant difference in MBC (post-relapse) survival between c-myc-nonamplified and c-myc-amplified subgroups regardless of or regarding the treatment. However, correlation was found between c-myc status and individual patient's outcomes. Patients with c-myc amplification treated with chemotherapy (CMF and FAC) had clinical benefit (complete remission, partial remission or stable disease) in contrast to patients without amplification. Lack of significant difference in MBC (post-relapse) survival according to c-myc status could be due to a better response of patients to appropriate treatment (chemotherapy). It is possible that negative prognostic impact of c-myc amplification is masked with increased responsiveness to chemotherapy.