New highlights on stroma–epithelial interactions in breast cancer

Although the stroma in which carcinomas arise has been previously regarded as a bystander to the clonal expansion and acquisition of malignant characteristics of tumor cells, it is now generally acknowledged that stromal changes are required for the establishment of cancer. In the present article, we discuss three recent publications that highlight the complex role the stroma has during the development of cancer and the potential for targeting the stroma by therapeutic approaches.     

Absence of epidermal growth factor receptor exon 18–21 mutation in hepatocellular carcinoma

For breast cancer management biopathologic profile and particularly the expression of estrogen receptor (ER) and progesterone receptor (PR) is considered essential. In advanced cases, core biopsy results are the only data available. To evaluate reliability of data, results of ER, PR, MIB1, p53 and c-erbB2 on core biopsy were compared with those on surgical specimens. Results showed a statistically significant concordance for ER and PR in pT1 but not in pT2 tumors, possibly due to breast cancer heterogeneity. MIB1 results were worse with no significant concordance even for pT1 group. There was statistically significant concordance in pT1 and pT2 groups for p53 and c-erbB 2, probably due to the high number of negative cases for these markers. We recommend more core biopsies for larger tumors since core biopsy has a high probability for giving unreliable data in these cases. In conclusion, this study showed that core biopsy has a high probability for not very reliable data in bigger tumors where the results obtained might be the only data available. A higher number of core biopsy is recommended in those cases.     

Influence of stromal–epithelial interactions on breast cancer in vitro and in vivo

Stromal cell-secreted chemokines including CCL2 have been implicated in the primary tumor microenvironment, as mediators of tumor cell migration, proliferation, and angiogenesis. Expression of CCL2 and its principal receptor CCR2 was analyzed by RQ-PCR in primary tumor cells and breast cancer cell lines. Breast cancer cell lines (MDA-MB-231, T47D) were co-cultured directly on a monolayer of primary breast tumor and normal stromal cells, retrieved using EpCAM+ magnetic beads, and changes in expression of CCL2, CCR2, MMP11, ELK1, VIL2, and Ki67 detected by RQ-PCR. Epithelial cell migration and proliferation in response to stromal cell-secreted factors was also analyzed. In vivo, tumor xenografts were formed by co-injecting T47D cells with primary tumor stromal cells. Following establishment, tumors were harvested and digested, epithelial cells retrieved and analyzed by RQ-PCR. Whole tumor tissue was also analyzed by immunohistochemistry for CD31 and the VIL2 encoded protein Ezrin. Tumor stromal cells expressed significantly higher levels of CCL2 than normal cells, with no CCR2 expression detected. Primary epithelial cells and breast cancer cell lines expressed elevated CCL2, with relative expression of CCR2 found to be higher than the ligand. Interaction of breast cancer epithelial cells with primary tumor, but not normal stromal cells, stimulated increased expression of CCL2 (8-fold), ELK1 (6-fold), VIL2 (6-fold), and MMP11 (17-fold). Factors secreted by stromal cells, including CCL2, stimulated a significant increase in epithelial cell migration, with no effect on cell proliferation in vitro observed. In vivo, the presence of stromal cells resulted in tumors of increased volume, mediated at least in part through neoangiogenesis demonstrated by immunohistochemistry (CD31). Admixed tumor xenografts exhibited increased expression of Ki67, MMP11, VIL2, and ELK1. Elevated Ezrin protein was also detected, with increased cytoplasmic localization. The results presented highlight mechanisms through which breast cancer epithelial cells can harness stromal cell biology to support tumor progression.     

C–X–C ligand 10 and C–X–C receptor 3 status can predict tamoxifen treatment response in breast cancer patients

To investigate the expression levels of CXCL10 and CXCR3 in tumors from breast cancer patients randomized to adjuvant tamoxifen treatment or no endocrine treatment, in order to further study the connection to prognosis and prediction of tamoxifen treatment outcome. Immunohistochemistry on tissue microarrays from 912 breast cancer patients randomized to tamoxifen or no endocrine treatment. CXCR3 status was found to be a prognostic tool in predicting distant recurrence, as well as reduced breast cancer-specific survival. In patients with estrogen receptor (ER)-positive tumors, tumors with strong CXCL10 levels had improved effect of tamoxifen treatment in terms of local recurrence-free survival [risk ratio (RR) 0.46 (95 % CI 0.25–0.85, P = 0.01)] compared with patients with tumors expressing weak CXCL10 expression. Further, patients with ER-positive tumors with strong CXCR3 expression had an improved effect of tamoxifen in terms of breast cancer-specific survival [RR 0.34 (95 % CI 0.19–0.62, P < 0.001)] compared with the group with weak CXCR3 levels [RR 1.33 (95 % CI 0.38–4.79, P = 0.65)]. We show here for the first time that CXCL10 and CXCR3 expression are both predictors of favorable outcome in patients treated with tamoxifen.     

Cost-effectiveness of lapatinib plus letrozole in her2-positive,hormone receptor–positive metastatic breast cancer in Canada

Background

The cost-effectiveness of first-line treatment with lapatinib plus letrozole for postmenopausal women with hormone receptor–positive (hr+), human epidermal growth factor receptor 2–positive (her2+) metastatic breast cancer (mbc) has not been assessed from the Canadian health care system and societal perspectives.

Methods

A partitioned survival analysis model with 3 health states (alive, pre-progression; alive, post-progression; dead) was developed to estimate direct and indirect costs and quality-adjusted life years (qalys) with lapatinib–letrozole, letrozole, anastrozole, or trastuzumab–anastrozole as first-line treatment. Clinical inputs for lapatinib–letrozole and letrozole were taken from the EGF30008 trial ({"type":"clinical-trial","attrs":{"text":"NCT00073528","term_id":"NCT00073528"}}NCT00073528). Clinical inputs for anastrozole and trastuzumab–anastrozole were taken from a network meta-analysis of published studies. Drug costs were obtained from the manufacturer’s price list, the Quebec list of medications, and imsBrogan. Other costs were taken from the Ontario Health Insurance Plan’s Schedule of Benefits and Fees and published studies. A 10-year time horizon was used. Costs and qalys were discounted at 5% annually. Deterministic and probabilistic sensitivity analyses were performed to assess the effects of changes in model parameters.

Results

Quality-adjusted life years gained with lapatinib–letrozole were 0.236 compared with trastuzumab–anastrozole, 0.440 compared with letrozole, and 0.568 compared with anastrozole. Assuming a health care system perspective, incremental costs were $5,805, $67,029, and $67,472 respectively. Given a cost per qaly threshold of $100,000, the probability that lapatinib–letrozole is preferred was 21% compared with letrozole, 36% compared with anastrozole, and 68% compared with trastuzumab–anastrozole. Results from the societal perspective were similar.

Conclusions

In postmenopausal women with hr+/her2+ mbc receiving first-line treatment, lapatinib–letrozole may not be cost-effective compared with letrozole or anastrozole, but may be cost-effective compared with trastuzumab–anastrozole.     

Predictors of timing of adjuvant chemotherapy in older women with hormone receptor–negative,stages II–III breast cancer

Adherence to consensus guidelines for cancer care may vary widely across health care settings and contribute to differences in cancer outcomes. For some women with breast cancer, omission of adjuvant chemotherapy or delays in its initiation may contribute to differences in cancer recurrence and mortality. We studied adjuvant chemotherapy use among women with stage II or stage III, hormone receptor–negative breast cancer to understand health system and socio-demographic correlates of underuse and delayed adjuvant chemotherapy. We used Surveillance Epidemiology and End Results (SEER)-Medicare linked data to examine the patterns of care for 6,678 women aged 65 and older diagnosed with stage II or stage III hormone receptor–negative breast cancer in 1994–2002, with claims data through 2007. Age-stratified logistic regression was employed to examine the potential role of socio-demographic and structural/organizational health services characteristics in explaining differences in adjuvant chemotherapy initiation. Overall utilization of guideline-recommended adjuvant chemotherapy peaked at 43% in this population. Increasing age, higher co-morbidity burden, and low-income status were associated with lower odds of chemotherapy initiation within 4 months, whereas having positive lymph nodes, more advanced disease, and being married were associated with higher odds (P < 0.05). Health system–related structural/organizational characteristics and race/ethnicity offered little explanatory insight. Timely initiation of guideline-recommended adjuvant chemotherapy was low, with significant variation by age, income, and co-morbidity status. Based on these findings, future studies should seek to explore the more nuanced reasons why older women do not receive chemotherapy and why delays in care occur.     

Impact of clinical tumor–node–metastasis staging on survival in gastric carcinoma patients receiving surgery

Background

Preoperative clinical staging of gastric cancer is used to determine therapeutic strategies. However, the impact of the clinical stage on survival has not been completely investigated, although the relationship between pathologic staging and survival outcome has been reported. The aim of the present study was to clarify the predictability of patient survival based on clinical staging and to evaluate the usefulness of staging as an indicator for selecting the treatment modality.

Methods

A total of 3033 patients who underwent surgery for gastric cancer were included. A survival analysis was conducted based on the seventh edition of the tumor–node–metastasis (TNM) clinical staging system of the American Joint Committee on Cancer. The predictive ability of the TNM clinical stage for survival was evaluated by Harrell’s C-index, a measure of the separation of survival distributions.

Results

The cumulative 5-year survival rates according to the clinical stage were 94.3 % (IA), 84.7 % (IB), 71.7 % (IIA), 56.1 % (IIB), 55.7 % (IIIA), 42.3 % (IIIB), 22.8 % (IIIC), and 9.1 % (IV). Although no significant difference was observed between clinical stages IIB and IIIA (p = 0.865), significant differences existed between all other clinical stages (p < 0.001). Harrell’s C-index applied to these results was 0.825 (95 % confidence interval 0.819–0.831).

Conclusions

The seventh edition of the TNM clinical staging system has a strong prognostic ability with a satisfactory C-index and should be considered valuable for selecting therapeutic strategies for the treatment of gastric cancer.

     

Stromal–epithelial interactions modulate cross-talk between prolactin receptor and HER2/Neu in breast cancer

Prolactin (PRL) promotes the proliferation and survival of breast cancer cells in part via the transactivation of human epidermal growth factor receptor 2 (HER2), also known as Neu in rodents. A PRL receptor (PRLR) antagonist, G129R, has been developed, which indirectly inhibits the tyrosine phosphorylation of HER2 (p-HER2) in human breast cancer cell lines. In this study, we investigate the effects of cancer-associated fibroblasts (CAFs) upon this molecular cross-talk using tumor cells and CAFs derived from spontaneous mammary tumors of female MMTV-neu transgenic mice. Tumors were resected and cultured as small tumor chunks (~3 mm3) or were cultured in monolayer. G129R reduced tyrosine phosphorylation of Neu (p-Neu) in a dose-dependent manner (IC50~10 μg/ml) in tumor chunks, but had no effect on primary tumor epithelial cells grown in monolayer. Direct co-culture of mouse or human tumor epithelial cell lines with CAFs restored the epithelial cells' response to G129R, similar to that observed in mouse tumor chunks. The addition of PRL, as expected, induced p-Neu in both the tumor chunk and co-culture models. The inhibitory effect of G129R was absent when CAFs were physically separated from mouse tumor epithelial cells using a transwell system, or when CAFs were replaced with normal fibroblasts in direct co-culture with human or mouse tumor epithelial cells. In vivo, G129R reduced p-Neu levels in primary mammary tumors of mice in a time- and dose-dependent manner. In conclusion, CAFs play a critical role in bridging the cross-talk between PRL and HER2/Neu in both mouse and human models of breast cancer. The inhibitory effects of G129R on p-Neu and on tumor growth are dependent upon interactions of tumor epithelial cells with CAFs.     

Influence of Sociodemographic Factors on Treatment Decisions in Non–Small-Cell Lung Cancer

IntroductionIn stage IV non–small-cell lung cancer (NSCLC), survival has significantly improved. Despite such trends, it has been noted that patients frequently refuse treatment. Therefore, we explored the factors associated with treatment refusal in NSCLC.Patients and MethodsUtilizing the National Cancer Data Base (NCDB), we identified all stage IV NSCLC cases from 2004 to 2014. Patients who received cancer treatment outside of the reporting facility were excluded. Multivariable logistic regression models were used to determine associations with treatment refusal.ResultsA total of 341,993 patients were identified; 5.4% of patients refused radiotherapy and 10.3% refused chemotherapy despite provider recommendations. The proportion of patients refusing radiotherapy and chemotherapy increased over time from 4.2% to 7.3% and 7.9% to 15%, respectively (P < .001). In multivariable analysis, men were less likely to refuse treatment compared to women (respectively, odds ratio = 0.80; 95% confidence interval, 0.76–0.84; P < .001; odds ratio = 0.82; 95% confidence interval, 0.80–0.85; P < .001, respectively). Factors associated with radiotherapy refusal included: Medicaid or Medicare as primary insurance, uninsured status, low household median income, and lower educational level. Regarding chemotherapy, uninsured patients, Medicaid patients, and patients with a high comorbidity index were more likely to refuse chemotherapy. Asians had lower rates of chemotherapy refusal relative to non-Hispanic whites. Non-Hispanic whites, Hispanics, and Asians had increasing chemotherapy refusal rates over time, while non-Hispanic blacks had less pronounced trends over time.ConclusionSocioeconomic factors rather than race/ethnicity appear to influence the refusal of cancer treatment in patients with stage IV NSCLC. Assessing socioeconomic challenges should be an essential part of patient evaluation when discussing treatment options.     

Influence of the C5a–C5a receptor system on breast cancer progression and patient prognosis

Background

Emerging evidence has shown activation of the complement system in cancer tissues and anaphylatoxin C5a release from C5 by cancer cells, suggesting C5a as a component in the cancer microenvironment. We revealed aberrant expression of C5a receptor (C5aR) in various human cancers and C5a-elicited enhancement of C5aR-expressing cancer cell invasion.

Methods

To explore an influence of the C5a–C5aR system in breast cancer (BC), we investigated BC C5aR expression in relation to clinicopathological parameters of the patients and an effect of C5a on BC cell proliferation.

Results

BC cell C5aR expression was observed immunohistochemically in 22 of 171 patients (13 %) and related to larger tumor size, higher nuclear grade and Ki-67 labeling index, presence of lymph node metastasis and advanced clinical stages. Interestingly, BC cells were C5aR-negative in all patients with BC in situ and C5aR-positive rate was high (38 %) in patients with hormone receptor-negative, namely triple-negative BC. For BC cells in metastasized lymph nodes, 12 of 22 patients (55 %) were C5aR-positive and included 7 patients with C5aR-negative BC in the primary site. Survival rate of patients with C5aR-positive BC was lower than that of patients with C5aR-negative BC. C5a enhanced proliferation of C5aR-expressing triple-negative BC cells in a C5aR-dependent manner.

Conclusion

Relation of BC C5aR expression to tumor development and poor prognosis of the patients and proliferation enhancing effect of C5a on C5aR-expressing BC cells suggest that the C5a–C5aR system is closely associated with BC progression. This system may be a new target to treat BC patients, particularly with triple-negative BC.

     

Clinical Impact of Hybrid Capture–Based Next-Generation Sequencing on Changes in Treatment Decisions in Lung Cancer

IntroductionTargeted therapy significantly prolongs survival in lung adenocarcinoma. Current diagnostic guidelines include only EGFR and anaplastic lymphoma receptor tyrosine kinase gene (ALK) testing. Next-generation sequencing (NGS) reveals more actionable genomic alterations than do standard diagnostic methods. Data on the influence of hybrid capture (HC)-based NGS on treatment are limited, and we investigated its impact on treatment decisions and clinical outcomes.MethodsThis retrospective study included patients with advanced lung cancer on whom HC-based NGS was performed between November 2011 and October 2015. Demographic and clinicopathologic characteristics, treatments, and outcome data were collected.ResultsA total of 101 patients were included (median age 63 years [53% females, 45% never-smokers, and 85% with adenocarcinoma]). HC-based NGS was performed upfront and after EGFR/ALK testing yielded negative or inconclusive results in 15% and 85% of patients, respectively. In 51.5% of patients, HC-based NGS was performed before first-line therapy, and in 48.5%, it was performed after treatment failure. HC-based NGS identified clinically actionable genomic alterations in 50% of patients, most frequently in EGFR (18%), Ret proto-oncogene (RET) (9%), ALK (8%), Mesenchymal-epithelial transition factor (MET) receptor tyrosine kinase gene (6%), and erb-b2 receptor tyrosine kinase 2 gene (ERBB2) (5%). In 15 patients, it identified EGFR/ALK aberrations after negative results of prior standard testing. Treatment strategy was changed for 43 patients (42.6%). The overall response rate in these patients was 65% (complete response 14.7%, partial response 50%). Median survival was not reached. Immunotherapy was administered in 33 patients, mostly without an actionable driver, with a presenting disease control rate of 32%, and with an association with tumor mutation burden.ConclusionsHC-based NGS influenced treatment decisions in close to half of the patients with lung adenocarcinoma and was associated with an overall response rate of 65%, which may translate into a survival benefit.     

Chemopreventive efficacy of rapamycin on Peutz–Jeghers syndrome in a mouse model

Germline mutations in LKB1 cause Peutz–Jeghers syndrome (PJS), an autosomal dominant disorder with a predisposition to gastrointestinal polyposis and cancer. Hyperactivation of mTOR-signaling has been associated with PJS. We previously reported that rapamycin treatment of Lkb1^+/− mice after the onset of polyposis reduced the polyp burden. Here we evaluated the preventive efficacy of rapamycin on Peutz–Jeghers polyposis. We found that rapamycin treatment of Lkb1^+/− mice initiated before the onset of polyposis in Lkb1^+/− mice led to a dramatic reduction in both polyp burden and polyp size and this reduction was associated with decreased phosphorylation levels of S6 and 4EBP1. Together, these findings support the use of rapamycin as an option for chemoprevention and treatment of PJS.     

Folate receptor specific anti-tumor activity of folate–mitomycin conjugates

PURPOSE: Folate receptor (FR) targeted drug conjugates were prepared by covalently attaching the vitamin folate, to the potent anticancer drug, mitomycin C (MMC). One such conjugate, called EC72, was synthesized with an intramolecular disulfide bond, and it was found to exhibit efficacious anti-tumor activity against FR-expressing M109 tumors in a manner that yielded no gross or microscopic toxicity, even to FR-positive kidneys. METHODS: EC72's specificity was demonstrated by two methods: (1) blocking EC72's activity with an excess of co-administered folic acid (FA) in M109 tumor bearing mice and (2) the absence of therapeutic activity in mice bearing FR-negative tumors. The importance of having a cleavable bond in the conjugate was also exemplified, since EC110 (a folate-MMC conjugate constructed with a more resilient amide bond) failed to produce anti-M109 tumor activity. EC72's therapeutic potential was found to decrease with respect to the increasing size of subcutaneous tumor. However, a combination therapy with paclitaxel reproducibly improved the anti-tumor efficacy relative to either agent alone at well tolerated dose levels and with no apparent increase in toxicity. A more advanced folate-MMC conjugate was also synthesized in an effort to improve activity. Thus, EC118, a molecule constructed with both a reducible disulfide bond and an acid-labile hydrazone bond in the linker region, was tested and found to produce a significantly greater number of tumor regressions of more established M109 tumors than that achieved with EC72. CONCLUSION: Overall, these data indicate that folate-targeted drug therapy alone, or in combination with paclitaxel, may be a novel and effective clinical approach towards treating FR-positive cancers.     

Prognostic value of estrogen receptor α and progesterone receptor conversion in distant breast cancer metastases

BACKGROUND:

Changes in the receptor profile of primary breast cancers to their metastases (receptor conversion) have been described for the estrogen receptor α (ERα) and progesterone receptor (PR). The purpose of this study was to evaluate the impact of receptor conversion for ERα and PR on survival in a large group of distant non‐bone breast cancer metastases.

METHODS:

Receptor conversion was studied by immunohistochemistry in a group of 233 metastatic breast cancer patients. Kaplan‐Meier overall survival curves were plotted, and differences between the curves were analyzed by log‐rank analysis. The additional prognostic value of conversion to established prognosticators was studied by Cox regression.

RESULTS:

Overall survival of patients showing conversion from positive to negative ERα or PR, or from negative to positive ERα or PR, or remaining receptor negative was comparable, and significantly worse than patients remaining receptor positive. ERα or PR receptor conversion from positive in the primary breast tumor to negative in distant metastases has independent negative prognostic value.

CONCLUSIONS:

ERα or PR receptor conversion from positive in the primary breast cancer to negative in distant metastases has negative prognostic value. Cancer 2012. © 2012 American Cancer Society.     

Effect of α-difluoromethyl-ornithine on the expression and function of the epidermal growth factor receptor in human breast epithelial cells in culture

We have previously shown that ornithine decarboxylase (ODC) overexpression enhances the transforming effects of HER-2neu and epidermal growth factor (EGF) in normal MCF-10A human breast epithelial cells. Our data suggest that such potentiation may be mediated by activation of the mitogen-activated protein kinase (MAPK) pathway and, possibly, STAT signalling. To further explore the interaction between the polyamine pathway and EGF/HER-2neu signalling in this system, we inhibited endogenous ODC activity with -difluoromethylornithine (DFMO) and assessed the effects of this blockade on the expression of EGF receptors (EGFR) and HER-2neu as well as activation of downstream EGF target genes. We found that DFMO administration to MCF-10A cells increased EGF-R mRNA and protein levels in a dose-response fashion, while HER-2neu expression was not affected. The effect of DFMO was mediated through polyamine depletion since it could be reversed by exogenous putrescine administration. Our results also indicated that the increase in EGFR induced by DFMO was not a non-specific consequence of inhibition of cell proliferation. The upregulated EGFRs were functional since they could be phosphorylated by EGF and they were able to promote phosphorylation of downstream signalling molecules including ERK, STAT-3, and STAT-5. We propose that physiologic levels of ODC activity may be critical for regulation of a yet undefined signalling pathway, whose blockade by DFMO leads to a compensatory increase in functional EGFR.     

Economic evaluation of hormonal therapies for postmenopausal women with estrogen receptor–positive early breast cancer in Canada

Background

Aromatase inhibitor (ai) therapy has been subjected to numerous cost-effectiveness analyses. However, with most ais having reached the end of patent protection and with maturation of the clinical trials data, a re-analysis of ai cost-effectiveness and a consideration of ai use as part of sequential therapy is desirable. Our objective was to assess the cost-effectiveness of the 5-year upfront and sequential tamoxifen (tam) and ai hormonal strategies currently used for treating patients with estrogen receptor (er)–positive early breast cancer.

Methods

The cost-effectiveness analysis used a Markov model that took a Canadian health system perspective with a lifetime time horizon. The base case involved 65-year-old women with er-positive early breast cancer. Probabilistic sensitivity analyses were used to incorporate parameter uncertainties. An expected-value-of-perfect-information test was performed to identify future research directions. Outcomes were quality-adjusted life-years (qalys) and costs.

Results

The sequential tam–ai strategy was less costly than the other strategies, but less effective than upfront ai and more effective than upfront tam. Upfront ai was more effective and less costly than upfront tam because of less breast cancer recurrence and differences in adverse events. In an exploratory analysis that included a sequential ai–tam strategy, ai–tam dominated based on small numerical differences unlikely to be clinically significant; that strategy was thus not used in the base-case analysis.

Conclusions

In postmenopausal women with er-positive early breast cancer, strategies using ais appear to provide more benefit than strategies using tam alone. Among the ai-containing strategies, sequential strategies using tam and an ai appear to provide benefits similar to those provided by upfront ai, but at a lower cost.