Chemokine receptor CXCR4 overexpression predicts recurrence for hormone receptor-positive, node-negative breast cancer patients.

BACKGROUND: The expected outcome for hormone receptor-positive, node-negative patients should be favorable. However, some patients do develop metastatic disease and the mechanism for this observation is poorly understood. CXCR4 is a chemokine receptor that has been implicated to play a pivotal role in breast cancer growth and metastasis. Its predictive role has not been fully evaluated. We determined to see whether CXCR4 can predict outcome in this subset of patients. METHODS: We accrued and analyzed data from 101 patients with hormone receptor-positive, node-negative breast cancers. The CXCR4 level was detected using Western blots and its level was defined as either low (<6.6-fold) or high (≥6.6-fold). Primary end points were systemic cancer recurrence and death. Statistical analysis performed included Spearman's correlation, Kaplan-Meier survival analysis, and Cox proportional hazard model. RESULTS: Although benign breast tissues had an undetectable level of CXCR4, all 101 cancer specimens had overexpressed CXCR4 (mean 6.4 ± 3.4-fold). There were 79 patients in the low CXCR4 group and 22 patients in the high CXCR4 group. High CXCR4 overexpression was predictive of both cancer recurrence (P = .002) and overall survival (P = .0012). CONCLUSION: High CXCR4 overexpression in primary tumors was predictive of worse outcomes in hormone receptor-positive, node-negative breast cancer patients.

High chemokine receptor CXCR4 level in triple negative breast cancer specimens predicts poor clinical outcome.

INTRODUCTION: Basal-like tumors or triple negative breast cancers are those that lack hormone-receptor and HER-2 expressions. They are considered to be aggressive tumors, and molecular mechanism to account for this is poorly understood. CXCR4 is a chemokine receptor that has been linked to breast cancer invasion and metastasis. We postulate that high CXCR4 overexpression level in cancer specimens predicts a poor outcome in patients with triple negative breast cancers. METHODS: One hundred fifty-one patients with triple negative breast cancers were prospectively accrued and analyzed. All had undergone standardized treatment and surveillance protocols. From each specimen, CXCR4 levels were detected using Western blots. Results were quantified against 1 microg of HeLa cells (positive controls). CXCR4 expression was defined as high (>or=6-fold) or low (<6-fold). Primary endpoints were cancer recurrence and death. Statistical analysis performed included Kaplan-Meier survival analysis, log-rank test, and Cox proportional hazard model. RESULTS: At a median follow-up of 37 mo, patients whose tumors had high CXCR4 overexpression (>or=6-fold) had a significantly higher incidence of cancer recurrence (P=0.014) and cancer-related death (P=0.026) than those in the low CXCR4 group (<6-fold). After adjusting for tumor size and nodal status, the relative risk for cancer recurrence and death in the high CXCR4 group was 2.1-fold (P=0.007; 95% CI: 1.22 to 3.8) and 2-fold (P=0.047; 95% CI: 1.01 to 4.06) higher than those in the low CXCR4 group, respectively. CONCLUSION: High CXCR4 overexpression in cancer specimens predicts a worse outcome in patients who have triple negative breast cancer.

Elevated chemokine receptor CXCR4 expression in primary tumors following neoadjuvant chemotherapy predicts poor outcomes for patients with locally advanced breast cancer (LABC).

Purpose Patients with locally advanced breast cancer (LABC) have a poor outcome. A molecular predictor to identify at-risk patients is sorely needed. CXCR4 is a chemokine receptor that has been linked to breast cancer invasion and metastasis. We postulate that in patients with LABC, CXCR4 overexpression levels in cancer specimens following neoadjuvant chemotherapy predict cancer outcome. Experimental design 54 patients with LABC were prospectively accrued and analyzed. All had neoadjuvant chemotherapy and definitive surgical therapy. Study homogeneity was maintained by standardized treatment, surveillance, and compliance protocols. A 1 cm(3) cancer from the surgical specimens of each patient was retrieved for analysis. CXCR4 levels were detected using Western blots, and results were quantified against 1 mug of protein from HeLa cells. CXCR4 expression was defined as low (<6.6-fold) or high (> or =6.6-fold). Primary endpoints were cancer recurrence and death. Statistical analysis performed included independent samples t-test, chi-square test, Spearman Rank analysis, Kaplan-Meier survival analysis, log-rank test, and Cox proportional hazard model. Results With a median follow-up of 30 months, patients with high CXCR4 overexpression (> or =6.6-fold) had a significantly higher incidence of recurrence (P = 0.0006) and cancer death (P = 0.0128) than those with low CXCR4 overexpression (<6.6-fold). The relative risks for recurrence and death in the high CXCR4 group were 27.3-fold (95% CI: 6.2-120.8; P = 0.001) and 4.8-fold (95% CI: 1.5-15.0; P = 0.0076) higher, respectively than those in the low CXCR4 group. Conclusion High CXCR4 overexpression in specimens from LABC patients receiving neoadjuvant chemotherapy was predictive of cancer outcome.

A prospective trial on initiation factor 4E (eIF4E) overexpression and cancer recurrence in node-negative breast cancer.

BACKGROUND: Eukaryotic Initiation Factor 4E (eIF4E) plays a crucial role in translation control. High eIF4E increase in tumor specimens independently predicted recurrence by multivariate analysis. This prospective trial of node-negative only breast cancer patients was initiated to test the hypothesis that high eIF4E increase predicts cancer recurrence and death, independent of nodal status. METHODS: The trial was powered to detect a 2.4-fold increase in relative risk for cancer recurrence in 240 node-negative patients on the basis of high versus low eIF4E increase in tumor specimens (type I error = .05, statistical power = .08). eIF4E level was quantified by using Western blot test. Treatment and surveillance regimens were standardized. Primary endpoints were cancer recurrence and cancer-related death. RESULTS: Of the 242 patients accrued, 112 were in the low eIF4E group (<7.5-fold), 82 were in the intermediate eIF4E group (7.5- to 15-fold), and 48 were in the high eIF4E group (>15-fold). Patients in the high eIF4E group had a statistically significant higher rate of cancer recurrence and cancer-related death (P = .0001 and P < or = .0001, log rank test). The relative risk for cancer recurrence was 2.2-fold higher in the high eIF4E group (P = .001, Cox model), and 3.7-fold higher for cancer-related death (P = .0009). CONCLUSIONS: In node-negative breast cancer, high eIF4E increase predicted a higher rate of cancer recurrence and death. High eIF4E patients had a >2-fold increase in relative risk for cancer recurrence and nearly a 4-fold increase in relative risk for death. This supports our hypothesis that high eIF4E is an independent predictor for breast cancer outcome independent of nodal status.

eIF4E-targeted suicide gene therapy in a minimal residual mouse model for metastatic soft-tissue head and neck squamous cell carcinoma improves disease-free survival.

BACKGROUND: Translation initiation factor eIF4E unwinds long 5'-untranslated regions of certain tightly regulated mRNAs and, thereby, facilitates their translation into proteins. eIF4E has been shown to be overexpressed in a majority of solid tumors, including head and neck cancers. To exploit this dysregulation, a long 5'-untranslated region was spliced upstream of a thymidine kinase (Tk) gene to enhance translation of this "suicide" gene within cells overexpressing eIF4E. We investigated the efficacy of therapy with an adenovirus incorporating this novel suicide gene (Ad-HSV-UTk) following cytoreductive tumor surgery in improving disease-free and overall survival in a mouse soft-tissue metastasis model for head and neck squamous cell carcinoma. MATERIALS AND METHODS: SCC-7 (orally-derived mouse SCCa) cells were treated with Ad-HSV-Tk, Ad-HSV-UTk, Ad-null, or saline and characterized for eIF4E and Tk levels by Western blot analysis. Cytotoxicities for cells treated with Ad-HSV-Tk, Ad-HSV-UTk, or Ad-null were quantified by MTS assay. Mice bearing SCC-7-induced tumors received cytoreduction followed by Ad-HSV-UTk + ganciclovir (GCV) or control treatment and were followed for disease-free and overall survival. RESULTS: SCC-7 cells showed uniformly high levels of eIF4E but elevated Tk for Ad-HSV-Tk- and Ad-HSV-UTk-treated cells over Ad-null-treated cells. Cytotoxicities for Ad-HSV-Tk- and Ad-HSV-UTk-treated cells were, correspondingly, observed to be 100-fold more sensitive than Ad-null-treated cells to GCV treatment. Cytoreduced mice receiving Ad-HSV-UTk + GCV treatment showed significantly longer disease-free survival (P = 0.0045) than control arm mice. CONCLUSIONS: Ad-HSV-UTk suicide gene therapy prolonged disease-free survival in a mouse minimal residual soft-tissue head and neck squamous cell carcinoma metastasis model.

Translational research in breast cancer.

The discovery of 25,000 human genes from the Human Genome Project has had a dramatic impact on the translational landscape of human diseases. Nowhere is the impact more apparent than in the field of cancer, specifically breast cancer. Understanding of the malignant process at a molecular level, coupled with the discovery of novel molecular techniques, has shifted the paradigm of treating breast cancer from a clinical, population-based risk assessment model to one based on molecular classification of disease.

A novel suicide gene therapy targeting the overexpression of eukaryotic initiation factor 4E improves survival in a rat peritoneal carcinomatosis model.

BACKGROUND: Eukaryotic Initiation Factor 4E (eIF4E) is pivotal in translating mRNAs with complex 5' un-translated regions (UTRs). A target-specific gene therapy was developed by splicing a complex 5'UTR upstream of the herpes simplex virus thymidine kinase (TK) gene in an adenovirus vector (Ad-HSV-UTK). Translation of the suicide TK gene is restricted to cells that overexpress eIF4E. We investigated the efficacy of this novel therapy in a rat peritoneal carcinomatosis (PC) model. METHODS: A PC model was developed by implanting a syngeneic 0.25 cm(3) tumor into Fisher 344 rats' omentum. Rats were grouped as follow: No surgery (Ø CS), cytoreductive surgery alone (CS), and CS + Ad-HSV-UTK + gancyclovir (GCV). 10(9) Ad-HSV-UTK was injected intraperitoneally (i.p.) and GCV (50 mg/kg) was administered i.p. every other day, beginning on postoperative day 2. The Kaplan-Meier survival method and log-rank test were statistical tests used. RESULTS: Treated rats had a significantly longer median and overall survival than the Ø CS and CS groups (P = .012). The median survivals for the treated rats, Ø CS, CS were 18 days, 9 days, and 11 days, respectively. CONCLUSIONS: Treatment with a novel suicide gene therapy following cytoreductive surgery prolonged survival in a rat peritoneal carcinomatosis model.

Elevated levels of chemokine receptor CXCR4 in HER-2 negative breast cancer specimens predict recurrence.

INTRODUCTION: CXCR4 is a chemokine receptor that has recently been implicated to play a pivotal role in breast cancer growth and metastasis. In animal models, reduction of CXCR4 expression significantly abrogated metastatic disease and prolonged survival. In human breast cancers, CXCR4 overexpression may portend a worse clinical course. Recent data suggest that HER-2 up-regulates CXCR4, but whether this is applicable in the clinical setting is not known. In this study, we evaluated the role of CXCR4 overexpression in breast cancer and determined whether it can serve as a potential marker of tumor recurrence in HER-2 negative tumors. METHODS: One hundred three patients with stages I to III breast cancers and 6 benign breast tissues were prospectively accrued and analyzed. Study homogeneity was maintained by standardized treatment, surveillance, and compliance protocols. CXCR4 levels were detected using Western blots and results were quantified against 1 microg of HeLa cells (positive controls). HER-2 expression was evaluated using the Hercep program, (Dako Corp., Carpinteria, CA) with a positive result defined as > or = 2. CXCR4 expression was defined as low (<6.6-fold) or high (> or = 6.6-fold). Primary endpoints were cancer recurrence and death. Statistical analysis performed included Spearman's correlation, independent samples t-test, Kaplan-Meier survival analysis, and log-rank test. RESULTS: All 103 cancer specimens had CXCR4 overexpression (mean 6.6 +/- 4.7), while none of the 6 benign breast tissues had detectable level of CXCR4. There were 36 HER-2 (+) tumors and 67 HER-2 (-) tumors. There was no statistical significance in mean CXCR4 overexpression between HER-2 (+) [5.6] and HER-2 (-) [6.6] cancers (P = 0.3; independent samples t-test). Recurrences occurred in 18 of 103 patients (17%); 10 occurred in HER-2 (+) tumors, and 8 occurred in HER-2 (-) patients. CXCR4 expression level was not predictive of cancer recurrence (P = 0.80) or overall survival (P = 0.70) in the HER-2 (+) group. However, among HER-2 negative tumors, 7 of 8 recurrences occurred in the high CXCR4 group (P = 0.037). There was no correlation between the degree of CXCR4 overexpression with tumor size (r = 0.13, P = 0.22), nodal status (r = 0.019, P = 0.4), ER/PR status (r = 0.12, P = 0.29), and HER-2 status (r = 0.091, P = 0.36). CONCLUSIONS: CXCR4 overexpression was observed in all 103 breast cancer specimens but was undetectable in benign breast tissues. CXCR4 overexpression does not correlate with tumor size, nodal status, ER/PR status, and HER-2 status. High CXCR4 overexpression had a significant impact on disease-free survival in HER-2 negative breast cancer patients and may help identify a subset of HER-2 negative breast cancers that have a more aggressive biological behavior.

Correlation of TLK1B in elevation and recurrence in doxorubicin-treated breast cancer patients with high eIF4E overexpression.

BACKGROUND: Tousled-like kinase 1B (TLK1B), a mammalian threonine kinase, facilitates the repair of DNA breaks. Eukaryotic initiation factor 4E (eIF4E) overexpression leads to the upregulation of TLK1B. Doxorubicin, commonly used in the adjuvant setting for breast cancer, causes DNA breaks. We hypothesized that the degree of TLK1B elevation is correlated with eIF4E overexpression and translates clinically to an increased risk for recurrence in breast cancer patients treated with doxorubicin-based adjuvant chemotherapy. STUDY DESIGN: We prospectively accrued 152 patients with stage I to III breast cancer treated with a doxorubicin-based chemotherapy in an adjuvant setting. Standardized treatment and surveillance protocols were used. eIF4E and TLK1B protein levels were quantified using Western blots, and patients were divided into tertiles based on previously reported stratification of eIF4E and TLK1B levels. Primary end points were cancer recurrence and death. Statistical analysis included Spearman's correlation, Kaplan-Meier survival analysis, log rank test, and the Cox proportional hazard model. RESULTS: The degree of TLK1B overexpression was highly correlated with the degree of eIF4E elevation (r=0.25, p=0.0025, Spearman rank correlation). Patients whose tumors were in the highest tertile for eIF4E overexpression had a higher risk for cancer recurrence and cancer death (p=0.015 and 0.049, respectively, log rank test). After adjusting for T-stage, nodal status, age, and estrogen receptor and progesterone receptor status, patients with tumors in the highest tertile of TLK1B overexpression treated with doxorubicin were 1.7-fold more likely to suffer recurrence than those in the low TLK1B group treated similarly (p=0.0078, CI, 1.17 to 2.75, Cox model). CONCLUSIONS: TLK1B overexpression was highly correlated with the level of eIF4E elevation. High TLK1B in cancer specimens was associated with a higher risk for cancer recurrence in patients treated with doxorubicin-based adjuvant chemotherapy.