Tumor angiogenesis and metastasis--correlation in invasive breast carcinoma

BACKGROUND

Experimental evidence suggests that the growth of a tumor beyond a certain size requires angiogenesis, which may also permit metastasis. To investigate how tumor angiogenesis correlates with metastases in breast carcinoma, we counted microvessels (capillaries and venules) and graded the density of microvessels within the initial invasive carcinomas of 49 patients (30 with metastases and 19 without).

METHODS

Using light microscopy, we highlighted the vessels by staining their endothelial cells immunocytochemically for factor VIII. The microvessels were carefully counted (per 200x field), and their density was graded (1 to 4+), in the most active areas of neovascularization, without knowledge of the outcome in the patient, the presence or absence of metastases, or any other pertinent variable.

RESULTS

Both microvessel counts and density grades correlated with metastatic disease. The mean (+/- SD) count and grade in the patients with metastases were 101 +/- 49.3 and 2.95 +/- 1.00 vessels, respectively. The corresponding values in the patients without metastases were significantly lower--45 +/- 21.1 and 1.38 +/- 0.82 (P = 0.003 and P less than or equal to 0.001, respectively). For each 10-microvessel increase in the count per 200x field, there was a 1.59-fold increase in the risk of metastasis (95 percent confidence interval, 1.19 to 2.12; P = 0.003). The microvessel count and density grade also correlated with distant metastases. For each 10-microvessel increase in the vessel count per 200x field, there was a 1.17-fold increase in the risk of distant metastasis (95 percent confidence interval, 1.02 to 1.34; P = 0.029).

CONCLUSIONS

The number of microvessels per 200x field in the areas of most intensive neovascularization in an invasive breast carcinoma may be an independent predictor of metastatic disease either in axillary lymph nodes or at distant sites (or both). Assessment of tumor angiogenesis may therefore prove valuable in selecting patients with early breast carcinoma for aggressive therapy.

Analysis of circulating tumor DNA to monitor metastatic breast cancer

BACKGROUND

The management of metastatic breast cancer requires monitoring of the tumor burden to determine the response to treatment, and improved biomarkers are needed. Biomarkers such as cancer antigen 15-3 (CA 15-3) and circulating tumor cells have been widely studied. However, circulating cell-free DNA carrying tumor-specific alterations (circulating tumor DNA) has not been extensively investigated or compared with other circulating biomarkers in breast cancer.

METHODS

We compared the radiographic imaging of tumors with the assay of circulating tumor DNA, CA 15-3, and circulating tumor cells in 30 women with metastatic breast cancer who were receiving systemic therapy. We used targeted or whole-genome sequencing to identify somatic genomic alterations and designed personalized assays to quantify circulating tumor DNA in serially collected plasma specimens. CA 15-3 levels and numbers of circulating tumor cells were measured at identical time points.

RESULTS

Circulating tumor DNA was successfully detected in 29 of the 30 women (97%) in whom somatic genomic alterations were identified; CA 15-3 and circulating tumor cells were detected in 21 of 27 women (78%) and 26 of 30 women (87%), respectively. Circulating tumor DNA levels showed a greater dynamic range, and greater correlation with changes in tumor burden, than did CA 15-3 or circulating tumor cells. Among the measures tested, circulating tumor DNA provided the earliest measure of treatment response in 10 of 19 women (53%).

CONCLUSIONS

This proof-of-concept analysis showed that circulating tumor DNA is an informative, inherently specific, and highly sensitive biomarker of metastatic breast cancer. (Funded by Cancer Research UK and others.).

Phase III trial of nanoparticle albumin-bound paclitaxel compared with polyethylated castor oil-based paclitaxel in women with breast cancer

PURPOSE

ABI-007, the first biologically interactive albumin-bound paclitaxel in a nanameter particle, free of solvents, was compared with polyethylated castor oil-based standard paclitaxel in patients with metastatic breast cancer (MBC). This phase III study was performed to confirm preclinical studies demonstrating superior efficacy and reduced toxicity of ABI-007 compared with standard paclitaxel.

PATIENTS AND METHODS

Patients were randomly assigned to 3-week cycles of either ABI-007 260 mg/m(2) intravenously without premedication (n = 229) or standard paclitaxel 175 mg/m(2) intravenously with premedication (n = 225).

RESULTS

ABI-007 demonstrated significantly higher response rates compared with standard paclitaxel (33% v 19%, respectively; P = .001) and significantly longer time to tumor progression (23.0 v 16.9 weeks, respectively; hazard ratio = 0.75; P = .006). The incidence of grade 4 neutropenia was significantly lower for ABI-007 compared with standard paclitaxel (9% v 22%, respectively; P < .001) despite a 49% higher paclitaxel dose. Febrile neutropenia was uncommon (< 2%), and the incidence did not differ between the two study arms. Grade 3 sensory neuropathy was more common in the ABI-007 arm than in the standard paclitaxel arm (10% v 2%, respectively; P < .001) but was easily managed and improved rapidly (median, 22 days). No hypersensitivity reactions occurred with ABI-007 despite the absence of premedication and shorter administration time.

CONCLUSION

ABI-007 demonstrated greater efficacy and a favorable safety profile compared with standard paclitaxel in this patient population. The improved therapeutic index and elimination of corticosteroid premedication required for solvent-based taxanes make the novel albumin-bound paclitaxel ABI-007 an important advance in the treatment of MBC.

Trastuzumab Deruxtecan in Previously Treated HER2-Low Advanced Breast Cancer

BACKGROUND

Among breast cancers without human epidermal growth factor receptor 2 (HER2) amplification, overexpression, or both, a large proportion express low levels of HER2 that may be targetable. Currently available HER2-directed therapies have been ineffective in patients with these "HER2-low" cancers.

METHODS

We conducted a phase 3 trial involving patients with HER2-low metastatic breast cancer who had received one or two previous lines of chemotherapy. (Low expression of HER2 was defined as a score of 1+ on immunohistochemical [IHC] analysis or as an IHC score of 2+ and negative results on in situ hybridization.) Patients were randomly assigned in a 2:1 ratio to receive trastuzumab deruxtecan or the physician's choice of chemotherapy. The primary end point was progression-free survival in the hormone receptor-positive cohort. The key secondary end points were progression-free survival among all patients and overall survival in the hormone receptor-positive cohort and among all patients.

RESULTS

Of 557 patients who underwent randomization, 494 (88.7%) had hormone receptor-positive disease and 63 (11.3%) had hormone receptor-negative disease. In the hormone receptor-positive cohort, the median progression-free survival was 10.1 months in the trastuzumab deruxtecan group and 5.4 months in the physician's choice group (hazard ratio for disease progression or death, 0.51; P<0.001), and overall survival was 23.9 months and 17.5 months, respectively (hazard ratio for death, 0.64; P = 0.003). Among all patients, the median progression-free survival was 9.9 months in the trastuzumab deruxtecan group and 5.1 months in the physician's choice group (hazard ratio for disease progression or death, 0.50; P<0.001), and overall survival was 23.4 months and 16.8 months, respectively (hazard ratio for death, 0.64; P = 0.001). Adverse events of grade 3 or higher occurred in 52.6% of the patients who received trastuzumab deruxtecan and 67.4% of those who received the physician's choice of chemotherapy. Adjudicated, drug-related interstitial lung disease or pneumonitis occurred in 12.1% of the patients who received trastuzumab deruxtecan; 0.8% had grade 5 events.

CONCLUSIONS

In this trial involving patients with HER2-low metastatic breast cancer, trastuzumab deruxtecan resulted in significantly longer progression-free and overall survival than the physician's choice of chemotherapy. (Funded by Daiichi Sankyo and AstraZeneca; DESTINY-Breast04 ClinicalTrials.gov number, NCT03734029.).

Reduced cardiotoxicity and comparable efficacy in a phase IIItrial of pegylated liposomal doxorubicin HCl(CAELYX™/Doxil®) versus conventional doxorubicin forfirst-line treatment of metastatic breast cancer

BACKGROUND

This study was designed to demonstrate that efficacy [progression-free survival (PFS)] of CAELYX [pegylated liposomal doxorubicin HCl (PLD)] is non-inferior to doxorubicin with significantly less cardiotoxicity in first-line treatment of women with metastatic breast cancer (MBC).

PATIENTS AND METHODS

Women (n=509) with MBC and normal cardiac function were randomized to receive either PLD 50 mg/m2 (every 4 weeks) or doxorubicin 60 mg/m2 (every 3 weeks). Cardiac event rates were based on reductions in left ventricular ejection fraction as a function of cumulative anthracycline dose.

RESULTS

PLD and doxorubicin were comparable with respect to PFS [6.9 versus 7.8 months, respectively; hazard ratio (HR)=1.00; 95% confidence interval (CI) 0.82-1.22]. Subgroup results were consistent. Overall risk of cardiotoxicity was significantly higher with doxorubicin than PLD (HR=3.16; 95%CI 1.58-6.31; P<0.001). Overall survival was similar (21 and 22 months for PLD and doxorubicin, respectively; HR=0.94; 95%CI 0.74-1.19). Alopecia (overall, 66% versus 20%; pronounced, 54% versus 7%), nausea (53% versus 37%), vomiting (31% versus 19%) and neutropenia (10% versus 4%) were more often associated with doxorubicin than PLD. Palmar-plantar erythrodysesthesia (48% versus 2%), stomatitis (22% versus 15%) and mucositis (23% versus 13%) were more often associated with PLD than doxorubicin.

CONCLUSIONS

In first-line therapy for MBC, PLD provides comparable efficacy to doxorubicin, with significantly reduced cardiotoxicity, myelosuppression, vomiting and alopecia.

Chromosomal instability drives metastasis through a cytosolic DNA response

Chromosomal instability is a hallmark of cancer that results from ongoing errors in chromosome segregation during mitosis. Although chromosomal instability is a major driver of tumour evolution, its role in metastasis has not been established. Here we show that chromosomal instability promotes metastasis by sustaining a tumour cell-autonomous response to cytosolic DNA. Errors in chromosome segregation create a preponderance of micronuclei whose rupture spills genomic DNA into the cytosol. This leads to the activation of the cGAS-STING (cyclic GMP-AMP synthase-stimulator of interferon genes) cytosolic DNA-sensing pathway and downstream noncanonical NF-κB signalling. Genetic suppression of chromosomal instability markedly delays metastasis even in highly aneuploid tumour models, whereas continuous chromosome segregation errors promote cellular invasion and metastasis in a STING-dependent manner. By subverting lethal epithelial responses to cytosolic DNA, chromosomally unstable tumour cells co-opt chronic activation of innate immune pathways to spread to distant organs.

Prognostic and predictive value of the 21-gene recurrence score assay in postmenopausal women with node-positive, oestrogen-receptor-positive breast cancer on chemotherapy: a retrospective analysis of a randomised trial

BACKGROUND

The 21-gene recurrence score assay is prognostic for women with node-negative, oestrogen-receptor-positive breast cancer treated with tamoxifen. A low recurrence score predicts little benefit of chemotherapy. For node-positive breast cancer, we investigated whether the recurrence score was prognostic in women treated with tamoxifen alone and whether it identified those who might not benefit from anthracycline-based chemotherapy, despite higher risks of recurrence.

METHODS

The phase 3 trial SWOG-8814 for postmenopausal women with node-positive, oestrogen-receptor-positive breast cancer showed that chemotherapy with cyclophosphamide, doxorubicin, and fluorouracil (CAF) before tamoxifen (CAF-T) added survival benefit to treatment with tamoxifen alone. Optional tumour banking yielded specimens for determination of recurrence score by RT-PCR. In this retrospective analysis, we assessed the effect of recurrence score on disease-free survival by treatment group (tamoxifen vs CAF-T) using Cox regression, adjusting for number of positive nodes.

FINDINGS

There were 367 specimens (40% of the 927 patients in the tamoxifen and CAF-T groups) with sufficient RNA for analysis (tamoxifen, n=148; CAF-T, n=219). The recurrence score was prognostic in the tamoxifen-alone group (p=0.006; hazard ratio [HR] 2.64, 95% CI 1.33-5.27, for a 50-point difference in recurrence score). There was no benefit of CAF in patients with a low recurrence score (score <18; log-rank p=0.97; HR 1.02, 0.54-1.93), but an improvement in disease-free survival for those with a high recurrence score (score > or =31; log-rank p=0.033; HR 0.59, 0.35-1.01), after adjustment for number of positive nodes. The recurrence score by treatment interaction was significant in the first 5 years (p=0.029), with no additional prediction beyond 5 years (p=0.58), although the cumulative benefit remained at 10 years. Results were similar for overall survival and breast-cancer-specific survival.

INTERPRETATION

The recurrence score is prognostic for tamoxifen-treated patients with positive nodes and predicts significant benefit of CAF in tumours with a high recurrence score. A low recurrence score identifies women who might not benefit from anthracycline-based chemotherapy, despite positive nodes.

FUNDING

National Cancer Institute and Genomic Health.

Cytokeratin-positive cells in the bone marrow and survival of patients with stage I, II, or III breast cancer

BACKGROUND

Cytokeratins are specific markers of epithelial cancer cells in bone marrow. We assessed the influence of cytokeratin-positive micrometastases in the bone marrow on the prognosis of women with breast cancer.

METHODS

We obtained bone marrow aspirates from both upper iliac crests of 552 patients with stage I, II, or III breast cancer who underwent complete resection of the tumor and 191 patients with nonmalignant disease. The specimens were stained with the monoclonal antibody A45-B/B3, which binds to an antigen on cytokeratins. The median follow-up was 38 months (range, 10 to 70). The primary end point was survival.

RESULTS

Cytokeratin-positive cells were detected in the bone marrow specimens of 2 of the 191 control patients with nonmalignant conditions (1 percent) and 199 of the 552 patients with breast cancer (36 percent). The presence of occult metastatic cells in bone marrow was unrelated to the presence or absence of lymph-node metastasis (P=0.13). After four years of follow-up, the presence of micrometastases in bone marrow was associated with the occurrence of clinically overt distant metastasis and death from cancer-related causes (P<0.001), but not with locoregional relapse (P=0.77). Of 199 patients with occult metastatic cells, 49 died of cancer, whereas of 353 patients without such cells, 22 died of cancer-related causes (P<0.001). Among the 301 women without lymph-node metastases, 14 of the 100 with bone marrow micrometastases died of cancer-related causes, as did 2 of the 201 without bone marrow micrometastases (P<0.001). The presence of occult metastatic cells in bone marrow, as compared with their absence, was an independent prognostic indicator of the risk of death from cancer (relative risk, 4.17; 95 percent confidence interval, 2.51 to 6.94; P<0.001), after adjustment for the use of systemic adjuvant chemotherapy.

CONCLUSIONS

The presence of occult cytokeratin-positive metastatic cells in bone marrow increases the risk of relapse in patients with stage I, II, or III breast cancer.

Clinical validity of circulating tumour cells in patients with metastatic breast cancer: a pooled analysis of individual patient data

BACKGROUND

We aimed to assess the clinical validity of circulating tumour cell (CTC) quantification for prognostication of patients with metastatic breast cancer by undertaking a pooled analysis of individual patient data.

METHODS

We contacted 51 European centres and asked them to provide reported and unreported anonymised data for individual patients with metastatic breast cancer who participated in studies between January, 2003, and July, 2012. Eligible studies had participants starting a new line of therapy, data for progression-free survival or overall survival, or both, and CTC quantification by the CellSearch method at baseline (before start of new treatment). We used Cox regression models, stratified by study, to establish the association between CTC count and progression-free survival and overall survival. We used the landmark method to assess the prognostic value of CTC and serum marker changes during treatment. We assessed the added value of CTCs or serum markers to prognostic clinicopathological models in a resampling procedure using likelihood ratio (LR) χ(2) statistics.

FINDINGS

17 centres provided data for 1944 eligible patients from 20 studies. 911 patients (46·9%) had a CTC count of 5 per 7·5 mL or higher at baseline, which was associated with decreased progression-free survival (hazard ratio [HR] 1·92, 95% CI 1·73-2·14, p<0·0001) and overall survival (HR 2·78, 95% CI 2·42-3·19, p<0·0001) compared with patients with a CTC count of less than 5 per 7·5 mL at baseline. Increased CTC counts 3-5 weeks after start of treatment, adjusted for CTC count at baseline, were associated with shortened progression-free survival (HR 1·85, 95% CI 1·48-2·32, p<0·0001) and overall survival (HR 2·26, 95% CI 1·68-3·03) as were increased CTC counts after 6-8 weeks (progression-free survival HR 2·20, 95% CI 1·66-2·90, p<0·0001; overall survival HR 2·91, 95% CI 2·01-4·23, p<0·0001). Survival prediction was significantly improved by addition of baseline CTC count to the clinicopathological models (progression-free survival LR 38·4, 95% CI 21·9-60·3, p<0·0001; overall survival LR 64·9, 95% CI 41·3-93·4, p<0·0001). This model was further improved by addition of CTC change at 3-5 weeks (progression-free survival LR 8·2, 95% CI 0·78-20·4, p=0·004; overall survival LR 11·5, 95% CI 2·6-25·1, p=0·0007) and at 6-8 weeks (progression-free survival LR 15·3, 95% CI 5·2-28·3; overall survival LR 14·6, 95% CI 4·0-30·6; both p<0·0001). Carcinoembryonic antigen and cancer antigen 15-3 concentrations at baseline and during therapy did not add significant information to the best baseline model.

INTERPRETATION

These data confirm the independent prognostic effect of CTC count on progression-free survival and overall survival. CTC count also improves the prognostication of metastatic breast cancer when added to full clinicopathological predictive models, whereas serum tumour markers do not.

FUNDING

Janssen Diagnostics, the Nuovo-Soldati foundation for cancer research.

Assessment of cardiac dysfunction in a randomized trial comparing doxorubicin and cyclophosphamide followed by paclitaxel, with or without trastuzumab as adjuvant therapy in node-positive, human epidermal growth factor receptor 2-overexpressing breast cancer: NSABP B-31

PURPOSE

Trastuzumab is effective in treating human epidermal growth factor receptor 2 (HER2) -positive breast cancer, but it increases frequency of cardiac dysfunction (CD) when used with or after anthracyclines.

PATIENTS AND METHODS

National Surgical Adjuvant Breast and Bowel Project trial B-31 compared doxorubicin and cyclophosphamide (AC) followed by paclitaxel with AC followed by paclitaxel plus 52 weeks of trastuzumab beginning concurrently with paclitaxel in patients with node-positive, HER2-positive breast cancer. Initiation of trastuzumab required normal post-AC left ventricular ejection fraction (LVEF) on multiple-gated acquisition scan. If symptoms suggestive of congestive heart failure (CHF) developed, source documents were blindly reviewed by an independent panel of cardiologists to determine whether criteria were met for a cardiac event (CE), which was defined as New York Heart Association class III or IV CHF or possible/probable cardiac death. Frequencies of CEs were compared between arms.

RESULTS

Among patients with normal post-AC LVEF who began post-AC treatment, five of 814 control patients subsequently had confirmed CEs (four CHFs and one cardiac death) compared with 31 of 850 trastuzumab-treated patients (31 CHFs and no cardiac deaths). The difference in cumulative incidence at 3 years was 3.3% (4.1% for trastuzumab-treated patients minus 0.8% for control patients; 95% CI, 1.7% to 4.9%). Twenty-seven of the 31 patients in the trastuzumab arm have been followed for > or = 6 months after diagnosis of a CE; 26 were asymptomatic at last assessment, and 18 remained on cardiac medication. CHFs were more frequent in older patients and patients with marginal post-AC LVEF. Fourteen percent of patients discontinued trastuzumab because of asymptomatic decreases in LVEF; 4% discontinued trastuzumab because of symptomatic cardiotoxicity.

CONCLUSION

Administering trastuzumab with paclitaxel after AC increases incidence of CHF and lesser CD. Potential cardiotoxicity should be carefully considered when discussing benefits and risks of this therapy.

Group support for patients with metastatic cancer. A randomized outcome study

The effects of weekly supportive group meetings for women with metastatic carcinoma of the breast were systematically evaluated in a one-year, randomized, prospective outcome study. The groups focused on the problems of terminal illness, including improving relationships with family, friends, and physicians and living as fully as possible in the face of death. We hypothesized that this invention would lead to improved mood, coping strategies, and self-esteem among those in the treatment group. Eighty-six patients were tested at four-month intervals. The treatment group had significantly lower mood-disturbance scores on the Profile of Mood States scale, had fewer maladaptive coping responses, and were less phobic than the control group. This study provides objective evidence that a supportive group intervention for patients with metastatic cancer results in psychological benefit. Mechanisms underlying the effectiveness of this group intervention are explored.

Phase III trial of doxorubicin, paclitaxel, and the combination of doxorubicin and paclitaxel as front-line chemotherapy for metastatic breast cancer: an intergroup trial (E1193)

PURPOSE

Between February 1993 and September 1995, 739 patients with metastatic breast cancer were entered on an Intergroup trial (E1193) comparing doxorubicin (60 mg/m(2)), paclitaxel (175 mg/m(2)/24 h), and the combination of doxorubicin and paclitaxel (AT, 50 mg/m(2) and 150 mg/m(2)/24 h, plus granulocyte colony-stimulating factor 5 mg/kg) as first-line therapy. Patients receiving single-agent doxorubicin or paclitaxel were crossed over to the other agent at time of progression.

PATIENTS AND METHODS

Patients were well balanced for on-study characteristics.

RESULTS

Responses (complete response and partial response) were seen in 36% of doxorubicin, 34% of paclitaxel, and 47% of AT patients (P =.84 for doxorubicin v paclitaxel, P =.007 for v AT, P =.004 for paclitaxel v AT). Median time to treatment failure (TTF) is 5.8, 6.0, and 8.0 months for doxorubicin, paclitaxel, and AT, respectively (P =.68 for doxorubicin v paclitaxel, P =.003 for doxorubicin v AT, P =.009 for paclitaxel v AT). Median survivals are 18.9 months for patients taking doxorubicin, 22.2 months for patients taking paclitaxel, and 22.0 months for patients taking AT (P = not significant). Responses were seen in 20% of patients crossing from doxorubicin --> paclitaxel and 22% of patients crossing from paclitaxel --> doxorubicin (P = not significant). Changes in global quality-of-life measurements from on-study to week 16 were similar in all three groups.

CONCLUSION

(1) doxorubicin and paclitaxel, in the doses used here, have equivalent activity; (2) the combination of AT results in superior overall response rates and time to TTF; and (3) despite these results, combination therapy with AT did not improve either survival or quality of life compared to sequential single-agent therapy.

Extending survival with chemotherapy in metastatic breast cancer

Metastatic breast cancer (MBC) remains essentially incurable, and goals of therapy include the palliation of symptoms, delay of disease progression, and prolongation of overall survival time without negatively impacting quality of life. Anthracycline and taxane-based therapies have traditionally shown the highest degree of activity in MBC. Though numerous randomized clinical trials have shown improvements in overall response rates, few have found clear survival benefits. In recent years, however, there has been a small but growing series of clinical trials demonstrating modest, but meaningful survival advantages in metastatic disease. A common feature in many of these trials has been the use of a taxane, and more recently, a taxane combined with an antimetabolite. In addition, the development of targeted biologic agents active against MBC, such as trastuzumab and bevacizumab, has demonstrated great potential for enhancing the effects of chemotherapy and producing meaningful survival improvements. The role of the taxanes, antimetabolites, and biologics in extending survival in MBC is discussed.

Dynamics of genomic clones in breast cancer patient xenografts at single-cell resolution

Human cancers, including breast cancers, comprise clones differing in mutation content. Clones evolve dynamically in space and time following principles of Darwinian evolution, underpinning important emergent features such as drug resistance and metastasis. Human breast cancer xenoengraftment is used as a means of capturing and studying tumour biology, and breast tumour xenografts are generally assumed to be reasonable models of the originating tumours. However, the consequences and reproducibility of engraftment and propagation on the genomic clonal architecture of tumours have not been systematically examined at single-cell resolution. Here we show, using deep-genome and single-cell sequencing methods, the clonal dynamics of initial engraftment and subsequent serial propagation of primary and metastatic human breast cancers in immunodeficient mice. In all 15 cases examined, clonal selection on engraftment was observed in both primary and metastatic breast tumours, varying in degree from extreme selective engraftment of minor (<5% of starting population) clones to moderate, polyclonal engraftment. Furthermore, ongoing clonal dynamics during serial passaging is a feature of tumours experiencing modest initial selection. Through single-cell sequencing, we show that major mutation clusters estimated from tumour population sequencing relate predictably to the most abundant clonal genotypes, even in clonally complex and rapidly evolving cases. Finally, we show that similar clonal expansion patterns can emerge in independent grafts of the same starting tumour population, indicating that genomic aberrations can be reproducible determinants of evolutionary trajectories. Our results show that measurement of genomically defined clonal population dynamics will be highly informative for functional studies using patient-derived breast cancer xenoengraftment.

Differential reactivity of a novel monoclonal antibody (DF3) with human malignant versus benign breast tumors

We have defined a human breast tumor associated antigen using a murine monoclonal antibody (MAb DF3) prepared against a membrane-enriched fraction of a human breast carcinoma. This antigen has a MW of 290 kD and is detectable on the cell surface of human breast carcinoma cells using a live cell radioimmunoassay and fluorescence flow cytometry. More important, immunoperoxidase staining with MAb DF3 clearly distinguishes malignant and benign breast lesions. A cytoplasmic staining pattern has been observed with 40 of 51 (78%) breast carcinomas, but only one of 13 fibroadenoma or fibrocystic disease specimens. In contrast, reactivity of benign breast lesions with MAb DF3 primarily occurs along apical borders on ductules. These results demonstrate that the DF3 antigen is present on apical borders of more differentiated secretory mammary epithelial cells and in the cytosol of less differentiated cells.

Weekly trastuzumab and paclitaxel therapy for metastatic breast cancer with analysis of efficacy by HER2 immunophenotype and gene amplification

PURPOSE

This phase II study evaluated weekly trastuzumab and paclitaxel therapy in women with HER2-normal and HER2-overexpressing metastatic breast cancer. Efficacy was correlated with immunohistochemical and fluorescent in situ hybridization (FISH) assay results.

PATIENTS AND METHODS

Eligible patients had bidimensionally measurable metastatic breast cancer. Up to three prior chemotherapy regimens, including prior anthracycline and taxane therapy, were allowed. Trastuzumab 4 mg/kg and paclitaxel 90 mg/m2 were administered on week 1, with trastuzumab 2 mg/kg and paclitaxel 90 mg/m2 administered on subsequent weeks. HER2 status was evaluated using four different immunohistochemical assays and FISH.

RESULTS

Patients received a median of 25 weekly infusions (range, one to 85 infusions). Median delivered paclitaxel dose-intensity was 82 mg/m2/wk (range, 52 to 90 mg/m2/wk). The intent-to-treat response rate for all 95 patients enrolled was 56.8% (95% confidence interval, 47% to 67%). A response rate of 61.4% (4.5% complete response, 56.8% partial response) was observed in 88 fully assessable patients. In patients with HER2-overexpressing tumors, overall response rates ranged from 67% to 81% compared with 41% to 46% in patients with HER2-normal expression (ranges reflect the different assay methods used to assess HER2 status). Differences in response rates between patients with HER2-overexpressing tumors and those with normal HER2 expression were statistically significant for all assay methods, with CB11 and TAB250 antibodies and FISH having the strongest significance. Therapy was generally well tolerated, although three patients had serious cardiac complications.

CONCLUSION

Weekly trastuzumab and paclitaxel therapy is active in women with metastatic breast cancer. Therapy was relatively well tolerated; however, attention to cardiac function is necessary.

Primary and metastatic breast carcinoma: initial clinical evaluation with PET with the radiolabeled glucose analogue 2-[F-18]-fluoro-2-deoxy-D-glucose

The authors assessed whether breast cancers can be detected by means of positron emission tomography (PET) with the positron-emitter-labeled glucose analogue 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG). In 12 patients with primary and/or metastatic breast cancer, PET images of F-18 distribution in vivo were obtained approximately 1 hour after intravenous injection of 10 mCi of FDG. Scan findings were correlated with other imaging data and physical examination and biopsy results. Ten of 10 primary breast cancers were imaged by means of FDG PET with a tumor:background FDG uptake ratio of 8.1 (median). Ten of 10 bone metastases were imaged with a tumor:normal bone uptake ratio of 6.05 (median). Five of five known soft-tissue metastases and four previously unsuspected nodal lesions were found with PET. No false-positive foci of FDG uptake were demonstrated. In two cases with negative mammograms due to dense breast parenchyma, FDG PET clearly delineated the primary tumors. These preliminary data demonstrate the feasibility and substantial potential of PET scanning with FDG to detect and localize both primary and metastatic breast cancers.

Personalized Detection of Circulating Tumor DNA Antedates Breast Cancer Metastatic Recurrence

PURPOSE

Up to 30% of patients with breast cancer relapse after primary treatment. There are no sensitive and reliable tests to monitor these patients and detect distant metastases before overt recurrence. Here, we demonstrate the use of personalized circulating tumor DNA (ctDNA) profiling for detection of recurrence in breast cancer.

EXPERIMENTAL DESIGN

Forty-nine primary patients with breast cancer were recruited following surgery and adjuvant therapy. Plasma samples (n = 208) were collected every 6 months for up to 4 years. Personalized assays targeting 16 variants selected from primary tumor whole-exome data were tested in serial plasma for the presence of ctDNA by ultradeep sequencing (average >100,000X).

RESULTS

Plasma ctDNA was detected ahead of clinical or radiologic relapse in 16 of the 18 relapsed patients (sensitivity of 89%); metastatic relapse was predicted with a lead time of up to 2 years (median, 8.9 months; range, 0.5-24.0 months). None of the 31 nonrelapsing patients were ctDNA-positive at any time point across 156 plasma samples (specificity of 100%). Of the two relapsed patients who were not detected in the study, the first had only a local recurrence, whereas the second patient had bone recurrence and had completed chemotherapy just 13 days prior to blood sampling.

CONCLUSIONS

This study demonstrates that patient-specific ctDNA analysis can be a sensitive and specific approach for disease surveillance for patients with breast cancer. More importantly, earlier detection of up to 2 years provides a possible window for therapeutic intervention.

Fulvestrant versus anastrozole for the treatment of advanced breast carcinoma in postmenopausal women: a prospective combined analysis of two multicenter trials

BACKGROUND

Fulvestrant (ICI 182,780) is a new type of estrogen receptor (ER) antagonist that down-regulates the ER and has no known agonist effects. The authors report the prospectively planned combined analysis of data from 2 Phase III trials comparing fulvestrant 250 mg monthly (n=428) and anastrozole 1 mg daily (n=423) in postmenopausal women with advanced breast carcinoma (ABC) who previously had progressed after receiving endocrine treatment.

METHODS

The primary endpoint was time to progression (TTP). Secondary endpoints included objective response (OR), duration of response (DOR), and tolerability. The trials were designed to demonstrate superiority of fulvestrant over anastrozole. Noninferiority of fulvestrant versus anastrozole was determined using a retrospectively applied statistical test.

RESULTS

At a median follow-up of 15.1 months, approximately 83% of patients in each treatment arm had progressed. The median TTP was 5.5 months in the fulvestrant group and 4.1 months in the anastrozole group, and the OR rates were 19.2% and 16.5% for fulvestrant and anastrozole, respectively (although the difference between treatments was not statistically significant). In patients who responded, further follow-up (median, 22.1 months) was performed to obtain more complete information on DOR; the median DOR (from randomization to disease progression) in patients who responded to treatment was 16.7 months in the fulvestrant group and 13.7 months in the anastrozole group. In a statistical analysis of DOR (using all randomized patients; from the start of response to disease progression), DOR was significantly longer for patients in the fulvestrant group compared with patients in the anastrozole group. Both drugs were tolerated well; withdrawals due to drug-related adverse events were 0.9% and 1.2% in the fulvestrant group and the anastrozole group, respectively. The incidence of joint disorders was significantly lower in the fulvestrant group (P=0.0036).

CONCLUSIONS

Fulvestrant was tolerated well and was at least as effective as anastrozole in the second-line treatment of patients with ABC. This new hormonaltherapy may provide a valuable treatment option for ABC in postmenopausal women.

Inhibition of tissue factor signaling suppresses tumor growth

Coagulation activation by tissue factor (TF) is implicated in cancer progression, cancer-associated thrombosis and metastasis. The role of direct TF signaling pathways in cancer, however, remains incompletely understood. Here we address how TF contributes to primary tumor growth by using a unique pair of isotype-matched antibodies that inhibit either coagulation (monoclonal antibody [Mab]-5G9) or direct signaling (Mab-10H10). We demonstrate that the inhibitory antibody of direct TF-VIIa signaling not only blocks TF-VIIa mediated activation of PAR2, but also disrupts the interaction of TF with integrins. In epithelial and TF-expressing endothelial cells, association of TF with beta1 integrins is regulated by TF extracellular ligand binding and independent of PAR2 signaling or proteolytic activity of VIIa. In contrast, alpha3beta1 integrin association of TF is constitutive in breast cancer cells and blocked by Mab-10H10 but not by Mab-5G9. Mab-5G9 has antitumor activity in vivo, but we show here that Mab-10H10 is at least as effective in suppressing human xenograft tumors in 2 different models. Breast tumor growth was also attenuated by blocking PAR2 signaling. These results show that tumor cell TF-PAR2 signaling is crucial for tumor growth and suggest that anti-TF strategies can be applied in cancer therapy with minor impairment of TF-dependent hemostatic pathways.

Activity of exemestane in metastatic breast cancer after failure of nonsteroidal aromatase inhibitors: a phase II trial

PURPOSE

To evaluate the antitumor activity and toxicity of a new steroidal aromatase inactivator, exemestane, in postmenopausal women with metastatic breast cancer who had progressive disease (PD) after treatment with a nonsteroidal aromatase inhibitor.

PATIENTS AND METHODS

In this phase II trial, eligible patients were treated with exemestane 25 mg daily (n = 241) followed, at the time PD was determined, by exemestane 100 mg daily (n = 58).

RESULTS

On the basis of the intent-to-treat analysis by independent review, exemestane 25 mg produced objective responses in 6.6% of patients (95% confidence interval [CI], 3.8% to 10.6%) and overall success (complete response + partial response + no change for 24 weeks or longer) in 24.3% (95% CI, 19.0% to 30.2%). The median durations of objective response and overall success were 58.4 weeks (95% CI, 49.7 to 71.1 weeks) and 37.0 weeks (95% CI, 35.0 to 39.4 weeks), respectively. Increasing the dose of exemestane to 100 mg upon the development of PD produced one partial response (1.7%; 95% CI, 0.0% to 9.2%). Both dosages were well tolerated and were discontinued because of adverse events in only 1.7% of patients.

CONCLUSION

Exemestane 25 mg once daily seems to be an attractive alternative to chemotherapy for the treatment of patients with metastatic breast cancer after multiple hormonal therapies have failed.

Mouse models of breast cancer metastasis

Metastatic spread of cancer cells is the main cause of death of breast cancer patients, and elucidation of the molecular mechanisms underlying this process is a major focus in cancer research. The identification of appropriate therapeutic targets and proof-of-concept experimentation involves an increasing number of experimental mouse models, including spontaneous and chemically induced carcinogenesis, tumor transplantation, and transgenic and/or knockout mice. Here we give a progress report on how mouse models have contributed to our understanding of the molecular processes underlying breast cancer metastasis and on how such experimentation can open new avenues to the development of innovative cancer therapy.

Prognostic value of estrogen receptors in primary breast cancer

The estrogen receptor status in 335 primary breast carcinomas was correlated with disease-free interval, survival and site of recurrent disease. Estrogen receptor positive carcinomas had a longer disease-free interval, a longer survival (mastectomy-death) and a longer time interval between recurrence and death. These parameters were also influenced by the lymph node status at mastectomy. Estrogen receptor positive cancers had a significantly better chance of survival independent of lymph node status. Estrogen receptors also delayed recurrence in node-positive carcinomas, but this advantage gradually disappeared with increasing interval after mastectomy. Estrogen receptor positive or estrogen receptor negative primary carcinomas did not show any predilection for spread to any particular site.

Mechanisms of tumor cell extravasation in an in vitro microvascular network platform

A deeper understanding of the mechanisms of tumor cell extravasation is essential in creating therapies that target this crucial step in cancer metastasis. Here, we use a microfluidic platform to study tumor cell extravasation from in vitro microvascular networks formed via vasculogenesis. We demonstrate tight endothelial cell-cell junctions, basement membrane deposition and physiological values of vessel permeability. Employing our assay, we demonstrate impaired endothelial barrier function and increased extravasation efficiency with inflammatory cytokine stimulation, as well as positive correlations between the metastatic potentials of MDA-MB-231, HT-1080, MCF-10A and their extravasation capabilities. High-resolution time-lapse microscopy reveals the highly dynamic nature of extravasation events, beginning with thin tumor cell protrusions across the endothelium followed by extrusion of the remainder of the cell body through the formation of small (~1 μm) openings in the endothelial barrier which grows in size (~8 μm) to allow for nuclear transmigration. No disruption to endothelial cell-cell junctions is discernible at 60×, or by changes in local barrier function after completion of transmigration. Tumor transendothelial migration efficiency is significantly higher in trapped cells compared to non-trapped adhered cells, and in cell clusters versus single tumor cells.

Characterization of paired tumor and non-tumor cell lines established from patients with breast cancer

The goal of our study was to develop a panel of tumor cell lines along with paired non-malignant cell lines or strains collected from breast cancers, predominantly primary tumors. From a total of 189 breast tumor samples consisting of 177 primary tumors and 12 metastatic tissues, we established 21 human breast tumor cell lines that included 18 cell lines derived from primary tumors and 3 derived from metastatic lesions. Cell lines included those from patients with germline BRCA1 and FHIT gene mutations and others with possible genetic predisposition. For 19 tumor cell lines, we also established one or more corresponding non-malignant cell strains or B lymphoblastoid (BL) lines, which included 16 BL lines and 7 breast epithelial (2) or stromal (5) cell strains. The present report describes clinical, pathological and molecular information regarding the normal and tumor tissue sources along with relevant personal information and familial medical history. Analysis of the breast tumor cell lines indicated that most of the cell lines had the following features: they were derived from large tumors with or without axillary node metastases; were aneuploid and exhibited a moderate to poorly differentiated phenotype; were estrogen receptor (ER)- and progesterone receptor (PR)-negative; and overexpressed p53 and HER2/neu proteins. Of 13 patients with primary breast cancers receiving curative intent mastectomies, 7 were dead after a mean period of 10 months. Our panel of paired tumor and non-malignant cell lines should provide important new reagents for breast cancer research.