Timed flat infusion of 5-fluorouracil increases the tolerability of 5-fluorouracil/docetaxel regimen in metastatic breast cancer: a dose-finding study

A dose-finding study was undertaken to determine the maximum-tolerated dose, and the recommended dose of docetaxel in combination with 12-h timed (22:00-10:00) flat infusion of 5-fluorouracil (5-FU) in metastatic breast cancer patients. This schedule seems to reduce the occurrence of stomatitis of the docetaxel and infusional 5-FU regimen.     

Cisplatin and 5-fluorouracil in refractory breast cancer patients: A phase II study

Summary 24 patients with a median of 3 prior chemotherapy regimens were treated in our department with cisplatin 20 mg/m² (with pre- and posthydration) and 5-fluorouracil 200 mg/m² i.v. on day 1–5, every three weeks. 23 patients are evaluable; one had early death. 4 patients (17%) achieved a partial response, 8 had stable disease, and 11 progressed. Toxicity observed was moderate and no renal toxicity was noted. This study therefore shows tolerable toxicity but limited usefulness of adding cisplatin to 5-fluorouracil according to this schedule in these highly pretreated patients.     

Phase II study of docetaxel in combination with epirubicin and protracted venous infusion 5-fluorouracil (ETF) in patients with recurrent or metastatic breast cancer. A Yorkshire breast cancer research group study

This study was originally designed as a phase I/II study, with a dose escalation of docetaxel in combination with epirubicin 50 mg m(-2) and 5-fluorouracil (5-FU) 200 mg m(-2) day(-1). However, as dose escalation was not possible, the study is reported as a phase II study of the combination to assess response and toxicity. A total of 51 patients with locally advanced or metastatic breast cancer were treated on this phase II study, with doses of docetaxel 50 mg m(-2), epirubicin 50 mg m(-2) and infusional 5-FU 200 mg m(-2) day(-1) for 21 days. The main toxicity of this combination was neutropenia with 89% of patients having grade 3 and 4 neutropenia, and 39% of patients experiencing febrile neutropenia. Nonhaematological toxicity was mild. The overall response rate in the assessable patients was 64%, with median progression-free survival of 38 weeks, and median survival of 70 weeks. The ETF regimen was found to be toxic, and it was not possible to escalate the dose of docetaxel above the first dose level. This regimen has therefore not been taken any further, but as a development of this a new study is ongoing, combining 3-weekly epirubicin, weekly docetaxel and capecitabine, days 1-14.     

Relationship between 5-fluorouracil disposition, toxicity and dihydropyrimidine dehydrogenase activity in cancer patients

Background:Previous work demonstrated that 5-fluorouracil(5-FU) metabolism is a critical factor for treatment tolerability. Inorder to study the predictivity of pharmacokinetics with respect to theoccurrence of 5-FU toxicity, this study investigates the relationshipbetween the pharmacokinetics of 5-FU and its metabolite5-fluoro-5,6-dihydrouracil (5-FDHU), dihydropyrimidine dehydrogenase(DPD) activity in peripheral blood mononuclear cells (PBMNC) andtreatment tolerability. Patients and methods:Pharmacokinetics and metabolismof 5-FU and activity of DPD in PBMNC were examined in110 colorectal cancer patients given adjuvant 5-FU 370mg/m² plus L-folinic acid 100 mg/m² for five daysevery four weeks. Drug levels were examined by HPLC, while toxicitieswere graded according to WHO criteria. Results:DPD activity in patients with mild toxicities (WHOgrade 1) was 197.22 ± 11.34 pmol of 5-FDHU/min/mg of protein,while in five patients with grade 3–4 gastrointestinal toxicity,DPD ranged from low to normal values (range 31.12–182.37pmol/min/mg of protein). In these patients, 5-FU clearance (CL) waslower (range 14.12–25.17 l/h/m²), and the area underthe curve (AUC) was higher (range 14.70–26.20 h×µg/ml)than those observed in 84 patients with mild toxicities (CL, 56.30± 3.60 l/h/m²; AUC, 7.91 ± 0.44h×µg/ml). The severity of adverse events was associated withincreased 5-FU/5-FDHU AUC ratio and reduced 5-FU CL, while 5-FU and5-FDHU pharmacokinetics were not related to DPD activity. Conclusion:This study shows that DPD activity in PBMNC isunrelated to 5-FU/5-FDHU disposition and patients with severe toxicitydisplay marked pharmacokinetic alterations while a reduction of DPDactivity may not occur.     

Oxaliplatin plus high-dose leucovorin and 5-fluorouracil in pretreated advanced breast cancer: a phase II study.

BACKGROUND: The purpose of this study was to evaluate the efficacy and toxicity of oxaliplatin plus 5-fluorouracil (5-FU) and leucovorin (LV) in patients with metastatic breast cancer (MBC) previously treated with anthracyclines and taxanes. PATIENTS AND METHODS: Fifty anthracycline- and taxane-pretreated MBC patients were treated with oxaliplatin 85 mg/m(2) as a 2-h infusion on day 1, LV 200 mg/m(2)/day as a 2-h infusion followed by bolus 5-FU 400 mg/m(2)/day and a 22-h infusion of 5-FU 600 mg/m(2)/day for 2 consecutive days. Treatment was repeated every 3 weeks. Patients were evaluated for response every two cycles. RESULTS: The median age was 51 years (range 34-75). Twenty patients (40%) had received three or more chemotherapeutic regimens, 64% had three or four metastatic sites and 78% had visceral metastases. All patients had prior exposure to anthracyclines and taxanes. Based on an intention-to-treat analysis, one patient (2%) achieved a complete response and 16 (32%) a partial response, for a 34% overall response rate. Twenty-one patients (42%) had stable disease and 12 (24%) progressive disease. The median time to tumor progression was 5.3 months (range 0.5-12.8) and the median overall survival was 12.3 months (range 0.5-19.2). Toxicity was mild to moderate. Grade 3/4 neutropenia and thrombocytopenia occurred in 32% and 18%, respectively. Febrile neutropenia was experienced by three patients (6%), who were successfully treated. Grade 3/4 neurotoxicity was reported in 14% of the patients and gradually declined after treatment discontinuation. Cycle delays were reported in 28% of patients and dose reductions in 26%. Alopecia, nausea-vomiting, diarrhea and mucositis were not significant. There were no treatment-related deaths. CONCLUSION: The combination of oxaliplatin plus 5-FU/LV seems to be an active regimen in patients with MBC and prior exposure to anthracyclines and taxanes with a good safety profile. The incidence of severe toxicity was quite low and the compliance of patients to the treatment was satisfactory. The results obtained with this regimen could be considered encouraging in this heavily pretreated group of breast cancer patients with a high incidence of visceral metastases.     

Inhibition of tumor growth and metastasis by angiogenesis inhibitor TNP-470 on breast cancer cell lines in vitro and in vivo

Antitumor and antimetastatic activity of the angiogenesis inhibitor O-(chloroacetyl-carbamoyl) fumagillol (TNP-470), a semisynthetic analogue offumagillin, was evaluated in breast cancer cell lines. In an in vitro MTTassay, after 72 hrs continuous exposure to TNP-470, growth inhibition wasobserved in all seven cell lines of murine (JYG-A, JYG-B, DD-762, andBALB/c-MC) or human (KPL-1, MDA-MB-231, and MKL-F) origin, in which the50% inhibitory concentrations (IC₅₀) at 72 hrstreatment were 4.6, 4.4, 4.6, 10.1, 35.0, 25.3, and 33.4 µg/ml,respectively. In an in vivo assay using JYG-A, JYG-B, KPL-1, and MDA-MB-231cells by orthotopic (right thoracic mammary fat pad) transplantation infemale nude mice, TNP-470 at 30 or 50 mg/kg body weight was injected s.c.every other day from the day of tumor cell inoculation until the end of theexperiment. The inhibitory effect on primary tumor growth was obtained inall four cell lines in a dose-dependent manner. In the 50 mg/kgTNP-470-treated group, the reductions in tumor weight of the JYG-A, JYG-B,KPL-1, and MDA-MB-231 cells with respect to the controls were 50%,30%, 4%, and 49%, respectively. Metastasis was seen inthe JYG-A, JYG-B, and KPL-1 cells. The numbers of mice bearing pulmonarymetastases of JYG-A and JYG-B cells and regional axillary lymph nodemetastases of KPL-1 cells were reduced, and TNP-470 at the 50 mg/kg dose toKPL-1 cells significantly reduced lymph node metastases compared with thecontrol. Although the weight gain was retarded in the TNP-470-treated mice,weight loss was not seen. TNP-470 was highly effective in the treatment ofbreast cancer cells. These results suggest that the clinical use of TNP-470may be a promising treatment for breast cancer patients.     

Paclitaxel, vinorelbine and 5-fluorouracil in breast cancer patients pretreated with adjuvant anthracyclines

We investigated the activity and toxicity of a combination of vinorelbine (VNB), paclitaxel (PTX) and 5-fluorouracil (5-FU) continuous infusion administered as first-line chemotherapy in metastatic breast cancer patients pretreated with adjuvant anthracyclines. A total of 61 patients received a regimen consisting of VNB 25 mg m(-2) on days 1 and 15, PTX 60 mg m(-2) on days 1, 8 and 15 and continuous infusion of 5-FU at 200 mg m(-2) every day. Cycles were repeated every 28 days. Disease response was evaluated by both RECIST and World Health Organization (WHO) criteria. Objective responses were recorded in 39 of 61 patients (64.0%) assessed by WHO and in 36 of 50 patients (72.0%) assessable by RECIST criteria. Complete remission occurred in 15 (24.6%) and 14 patients (28.0%), respectively. The median time to progression and overall survival of entire population was 10.6 and 27.3 months, respectively, and median duration of complete response was 14.8 months. The dose-limiting toxicity was myelosuppression (leucopenia grade 3/4 in 52.5% of patients). Grade 3/4 nonhaematologic toxicities included mucositis/diarrhoea in 13.1%, skin in 3.3% and cardiac in 1.6% of patients. Grade 2/3 neurotoxicity was observed in five patients (7.2%). The VNB, PTX and 5-FU continuous infusion combination regimen was active and manageable. Complete responses were frequent and durable.     

Phase II study of a triplet regimen in advanced colorectal cancer using methotrexate, oxaliplatin and 5-fluorouracil

Building upon the concept of schedule-specific biochemical modulation of 5-fluorouracil (FU), which alternates bolus and continuous infusion (CI) FU, we have incorporated oxaliplatin (l-OHP) following the bolus part of the regimen to explore the activity of this new combination. Patients with advanced, untreated, measurable colorectal cancer received sequential methotrexate (MTX) (days 1 and 15)-->l-OHP+FU (days 2 and 16) (200, 85 and 600 mg m(-2), respectively) followed by 3 weeks of CI FU (200 mg m(-2) day(-1)) given from day 29 to 50, modulated by weekly leucovorin (LV) (20 mg m(-2)). After 1 week of rest, the second cycle was started. The treatment was continued until progression or patient's refusal. According to the intention-to-treat analysis on all 46 patients accrued, the response rate was 42% (95% CL=28-55%), with three complete responses and 16 partial responses. The median overall survival was 15.9 months and the median progression-free survival 6.9 months. Toxicity was very mild, with the bolus part of the regimen more toxic than the infusional part (24 vs 7% of grade III-IV, respectively). This new combination of MTX -->l-OHP-FU followed by FU CI is well tolerated, feasible and produces activity results similar to other more simple, but more toxic, regimens. Pros and cons of the different fluoropyrimidines-l-OHP combinations are discussed.     

乳腺癌患者心理健康状况与个性特点及其相关性的调查研究

目的探讨乳腺癌患者的心理健康状况和个性特征及其相关性因素.方法采用SCL-90、EPQ问卷对106例乳癌患者进行问卷测查.结果①SCL-90测试发现,乳癌患者的躯体化、焦虑、抑郁因子分显著高于常模和正常人群(P<0.01-0.05),而人际敏感和偏执显著低于正常人群(P<0.01);②乳腺癌患者个性测查虽然多为性格外向,但有明显的掩饰倾向;③乳癌患者SCL-90各因子分与EPQ中的情绪稳定性明显相关(P<0.0005),与精神质多数相关(P<0.01).④结论乳腺癌患者存在明显的焦虑、抑郁等不良的情绪反应,个性虽表现外向,但有明显的掩饰倾向.建议对乳腺癌患者实施有效的心理干预.     

The histone deacetylase inhibitor PXD101 synergises with 5-fluorouracil to inhibit colon cancer cell growth in vitro and in vivo

Abstract Purpose Histone deacetylase inhibitors (HDACi) inhibit the growth of cancer cells, and combinations of HDACi with established chemotherapeutics can lead to synergistic effects. We have investigated effects of PXD101 (HDACi in phase II clinical trials) in combination with 5-fluorouracil, on tumour cell proliferation and apoptosis both in vitro and in vivo. Experimental design HCT116 cells were studied using proliferation and clonogenic assays. Synergistic inhibition of proliferation and clonogenicity was determined by incubation with PXD101 and 5-fluorouracil, and analysis using CalcuSyn™ software. The effect of combining PXD101 and 5-fluorouracil on apoptosis was examined in vitro using PARP-cleavage and TUNEL. Finally, the effectiveness of combining PXD101 and 5-fluorouracil in vivo was tested using both HT-29 and HCT116 xenograft models. Results Synergistic inhibition of proliferation and clonogenicity was obtained when HCT116 cells were incubated with PXD101 and 5-fluorouracil. 5-fluorouracil combined with PXD101 also increased DNA fragmentation and PARP cleavage in HCT116 cells. Incubation with PXD101 down regulated thymidylate synthase expression in HCT116 cells. In vivo studies, using mouse HT29 and HCT116 xenograft models, showed improved reductions in tumour volume compared to single compound, when PXD101 and 5-fluorouracil were combined. Conclusions PXD101 and 5-fluorouracil synergistically combine in their anti-tumour effects against colon cancer cells in vitro and show enhanced activity when combined in vivo. Based on the results presented herein, a rationale for the use of PXD101 and 5-fluorouracil in combination in the clinic has been demonstrated.     

Weekly continuous infusion of 5-fluorouracil with oral leucovorin in metastatic breast cancer patients with primary resistance to doxorubicin

Doxorubicin-resistant metastatic breast cancer (MBC) is a very poor prognosis scenario, where only taxanes have shown activity, often at the expense of severe toxicity that compromises palliation. This study was undertaken to test the antitumor activity and tolerability of infusional 5-fluorouracil (5-FU) modulated with low-dose oral leucovorin (LV), in heavily pretreated patients with stringent criteria of primary resistance to doxorubicin, visceral involvement, and suboptimal performance status. Twenty-six patients with measurable MBC and primary resistance to anthracyclines received a weekly outpatient 48-hour infusion of high-dose 5-FU with low dose oral leucovorin. All patients were assessable for response and toxicity. Eight partial responses were seen (30% response rate) in soft tissue and visceral sites, with a median response duration of eight months (5 + to 12). 98% of the cycles were minimally toxic or non-toxic. Toxicities included mucositis, diarrhea, and plantar-palmar-syndrome. Our results suggest that this schedule of LV-modulated infusional 5-FU can produce a substantial number of long-lasting responses and meaningful palliation to this very poor prognosis population.     

Primary chemotherapy in operable breast cancer with favorable prognostic factors: A pilot study evaluating the efficacy of a regimen with a low subjective toxic burden containing vinorelbine, 5-fluorouracil and folinic acid (FLN)

Background: Biological considerations support the use of primary chemotherapy in operable breast cancer; and despite wide variations of used regimens, clinical studies consistently show a significant tumor response allowing breast conservation in many patients otherwise canditates for mastectomy. We investigated the efficacy and the acceptance of a combination chemotherapy with vinorelbine, 5-fluorouracil and high-dose folinic acid in operable breast cancer with favorable prognostic factors and tested the relationship of hormone receptor status, Ki67, p53, c-erbB2 and bcl-2 with treatment response.Patients and methods: Thirty-nine patients (median age 51 years, range 36–71 years), eight with T₁, twenty-eight with T₂ and two with T₃ lesions, were treated with 5-fluorouracil (350 mg/m₂, i.v. on day 1 to 3) preceded by folinic acid (100 mg/m² i.v. on day 1 to 3) and vinorelbine, given on days 1 and 3 at the dose of 20 mg/m² (FLN regimen). Therapy was administered on an outpatient basis every three weeks. Non responders had surgery after three courses, while complete or partial responders underwent surgery after six courses. All but one were evaluable for response and toxicity.Results: Objective responses were observed in 23 of the 38 evaluable patients (61%; 95% CI: 46%–76%): three complete responses (8%) and 20 partial responses (53%). Fifteen patients (39%) had stable disease, of whom nine (23%) had minor response. None of the patients had disease progression during treatment. Objective responses were significantly associated with no expression of estrogen and/or progesteron receptors and >50% decrease in Ki67 after induction chemotherapy. Tolerance was excellent and none of the patients experienced grade 2 alopecia.Conclusions: The moderate efficacy of this regimen might be partially due to the selection of patients with high expression of steroid hormone receptors and low proliferation rate, which have an unfavorable impact on response to this chemotherapy.     

The impact of bilateral breast cancer on the prognosis of breast cancer: a comparative study with unilateral breast cancer

BACKGROUND: The clinical significance of bilateral breast cancer is unclear and its influence on prognosis is controversial. We assessed the impact of synchronous and metachronous bilateral breast cancer on the prognosis compared with unilateral breast cancer. METHODS: Between January 1, 1960 and December 31, 2001, 1,214 women were treated for primary operable breast cancers. Thirteen (1.1%) had synchronous bilateral breast cancer; 33 (2.7%) had a metachronous contralateral breast cancer. We compared age at operation, menopausal status, clinical stage, tumor size and histology, lymph node status, hormone receptor status, and use of adjuvant chemotherapy or hormone therapy, and we analyzed the impact of these factors on recurrence and survival in the 46 patients with bilateral breast cancer and the 1,168 patients with unilateral breast cancer. RESULTS: The 5-and 10-year disease-free survival rates, respectively, were 65% and 65% in metachronous cases, 85.7% and 64.3% in synchronous cases, and 77.9% and 72.1% in unilateral cases. There was no significant difference in overall survival among the three groups. On multivariate analysis, metachronous bilaterality, tumor size, lymph node status and adjuvant hormone therapy were each independent risk factors for recurrence, whereas bilaterality of breast cancer did not influence overall survival. CONCLUSIONS: Our data suggest that metachronous bilateral breast cancer is associated with shorter disease-free survival than synchronous bilateral or unilateral breast cancer, although overall survival does not differ among the 3 groups. Patients with metachronous bilateral breast cancer should be followed particularly closely in order to detect recurrence early and maximize quality of life.     

In vitro andin vivo modulation of growth regulation in the human breast cancer cell line MCF-7 by estradiol metabolites

Background  The natural estrogen 17β-estradiol (E₂) functions as a potent tumor promoter during tumorigenic transformation of the mammary gland. From amongst the various pathways of E₂ metabolism upregulation of C16α-hydroxylation of E₂ has been associated with carcinogenesis. In the present studyin vitro andin vivo experiments were performed on estrogen receptor positive human breast cancer MCF-7 cells to examine whether the natural estrogen E₂ and its metabolites 16α-hydroxyestrone (16α-OHEi) and 2-hydroxyestrone (2-OHE₁) function as modulators of tumor cell growth. Methods  An anchorage-independent growth assay was used forin vitro study by counting the number of tri-dimensional colonies formed by MCF-7 cells suspended in 0.33% agar.In vivo experiments examined the effect of implanting metabolite material pellets into female nude mice. Results  In the anchorage-independent growth assay (AIG), continuous 14-day exposure to E₂ and to 16α-OHE₁ at 200 ng/ml induced a 59.4% and a 105.9% increase (P=0.001) respectively in the number of colonies of MCF-7 cells. Identical treatment with 2-OHE₁, however, failed to increase AIG relative to that seen in the solvent treated control cultures. In thein vivo tumorigenicity assay, treatment of nude mice with 1.5 mg E₂ or 16α-OHE₁ resulted in a 335.4% and a 384.1% increase (P<0.0002) in tumor growth, while identical treatment with 2-OHE₁ failed to exhibit any increase relative to the control group. Conclusions  These results suggest that the 16α- and 2-hydroxylated metabolites of E₂ may directly affectin vitro growth of MCF-7 cells via an autocrine mechanism andin vivo growth via paracrine mechanisms. Thus, E2-mediated growth regulation in MCF-7 cells may in part be due to distinct effects of specific E₂ metabolites on the breast cancer cells.     

五味子对乳腺癌细胞抑制作用的体外研究

目的:评估中药五味子抗癌有效成分木酚素及其代谢产物对雌激素受体阳性以及阴性的乳腺癌细胞株的体外作用,并评价五味子对于乳腺癌的体外杀伤作用。方法:利用ATP 生物荧光药物敏感性检测技术(ATP-TCA),检测五味子木酚素对50例乳腺癌的体外杀伤作用,并检测不同浓度五味子木酚素及其代谢物（END、ENL）对于ER（＋）的MCF-7、T47D和ER（－）的MDA-MB-231、MDA-MB-435细胞株的杀伤作用。评价五味子的体外作用有效率及其与雌激素受体表型是否相关。结果:五味子对乳腺癌患者的乳腺癌细胞具有明显的体外杀伤作用,体外有效率为34.0%(17/50);五味子木酚素以浓度依赖的方式,显著降低乳腺癌细胞株MCF-7、T47D、MDA-MB-435、MDA-MB-231的存活率,且该抑制作用和细胞雌激素受体的关系并不明显（P＞0.05）,五味子木酚素在较低浓度（0.1-30μmol/L）下对雌激素受体阳性乳腺癌细胞株MCF-7、T47D表现出促进增殖的作用,当浓度提高至100μmol/L后,五味子木酚素对MCF-7、T47D增殖表现出显著的抑制作用,并呈剂量-效应关系。木酚素的低浓度促进乳腺癌细胞增殖作用在雌激素受体阴性乳腺癌细胞株MDA-MB-435、MDA-MB-231中并不明显,当浓度提高至100μmol/L后,五味子木酚素对MDA-MB-435、MDA-MB-231增殖表现出显著的抑制作用,并呈剂量-效应关系。ENL、END(3-1000μmol/L)在体外对乳腺癌细胞株存在显著抑制作用（P＜0.05）,并有剂量依赖效应,未发现其与细胞雌激素受体表型有关联（P＞0.05）。木酚素在较低浓度区间（0.1-30μmol/L）促进ER(＋)细胞株的增殖,但对ER(－)细胞株作用不显著。结论:五味子对乳腺癌细胞系以及乳腺癌患者细胞均具有较强的杀伤作用,值得进一步临床研究和应用。     

Amphiregulin Antisense RNA Delivered by Adnovirus Suppresses Growth of Breast Cancer Cells In Vitro and In Vivo

OBJECTIVE To investigate the therapeutic potential of amphiregulin antisense RNA delivered by adenoviral vector in a human breast cancer model.METHODS Human amphiregulin cDNA was subcloned in the opposite orientation to the cytomegaloviral promoter and inserted into an E1/E3-deleted type 5 adenoviral vector to obtain an AdA4 construct which expresses amphiregulin antisense mRNA. Both in vitro and in vivo antiproliferative effects of the antisense RNA were studied by infecting transformed human breast epithelial NS2T2A1 cells and tumors.RESULTS Amphiregulin protein expression was inhibited dramatically in the NS2T2A1 cells after infection with AdA4. The in vitro cell growth was inhibited significantly at day 4 post-AdA4 infection compared with control empty virus AdC1 at a MOl of 200 and 400 pfu/cell to 69.3% and 49.8%, respectively (P<0.02, P<0.005). After 3 intra-tumoral injections of 109 pfu AdA4, tumor volumes were reduced to 40.6% of that of the control group at day 35 (P<0.005).CONCLUSION The transfer of amphiregulin RNA antisense by adenoviral vector is effective for amphiregulin targeting strategy, leading to an inhibition of in vitro cell proliferation and in vivo tumor growth in this breast cancer model.     

Suppressing NRIP1 inhibits growth of breast cancer cells in vitro and in vivo

Earlier age at menarche is a major risk factor for breast cancer. Our previous study identified Nrip1 (also known as Rip140) as a candidate gene for delaying female sexual maturation (FSM) and found that knocking out Nrip1 could significantly delay FSM in mice. To investigate the effects of NRIP1 in breast cancer we used human cell lines and tissue arrays along with an in vivo study of DMBA-induced carcinogenesis in Nrip1 knockout mice. Analysis of tissue arrays found that NRIP1 is elevated in tumors compared to cancer adjacent normal tissue. Interestingly, in benign tumors NRIP1 levels are higher in the cytosol of stromal cells, but NRIP1 levels are higher in the nuclei of epithelial cells in malignancies. We also found overexpression of NRIP1 in breast cancer cell lines, and that suppression of NRIP1 by siRNA in these cells significantly induced apoptosis and inhibited cell growth. Furthermore, in vivo data suggests that NRIP1 is upregulated in DMBA-induced breast cancer. Importantly, we found that DMBA-induced carcinogenesis is suppressed in Nrip1 knockdown mice. These findings suggest that NRIP1 plays a critical role in promoting the progression and development of breast cancer and that it may be a potential therapeutic target for the new breast cancer treatments.