Efeitos de diferentes doses de tamoxifeno sobre a proliferação celular do epitélio mamário

Facina, Gil; Baracat, Edmund Chada; Lima, Geraldo Rodrigues de; Gebrim, Luíz Henrique

doi:10.1590/s0100-72032003000300007

Cited by 4 publications

(3 citation statements)

References 20 publications

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“…In addition to results obtained by other authors [ 2 , 3 , 41 , 42 ], our results support the need to conduct clinical trials on adjuvant therapy and chemoprevention with low-dose tamoxifen, to provide comprehensive and low cost medical care for women with breast cancer.…”

Section: Discussionsupporting

confidence: 87%

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Effects of low-dose tamoxifen on breast cancer biomarkers Ki-67, estrogen and progesterone receptors

Sousa¹,

Facina

Silva

et al. 2006

Int Semin Surg Oncol

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Breast carcinoma is the most common malignancy among women and it has a major impact on mortality. Studies of primary chemoprevention with tamoxifen have generated high expectations and considerable success rates. The efficacy of lower doses of tamoxifen is similar to that seen with a standard dose of the drug, and there has been a reduction in healthcare costs and side effects.The immune reaction to monoclonal antibody Ki-67 (MIB-1) and the expression of estrogen receptors (1D5) and progesterone receptors (PgR 636) in breast carcinoma were studied in patients treated with 10 mg of tamoxifen for a period of 14 days.A prospective randomized clinical trial was conducted with 38 patients divided into two groups: Group A: N = 20 (control group-without medication) and Group B: N = 18 (tamoxifen/10 mg/day for 14 days). All patients signed an informed consent term previously approved by both institutions. Patients underwent incisional biopsy before treatment and 14 days later a tumor tissue sample was obtained during surgical treatment. Positivity was quantitatively assessed, counting at least 1.000 cells per slide. For statistical data analysis, a Wilcoxon non-parametric test was used, and α was set at 5%.Both groups (A and B) were considered homogeneous regarding control variables. In Group A (control), there was no statistically significant reduction in Ki-67 (MIB-1) (p = 0.627), estrogen receptor (1D5) (p = 0.296) and progesterone receptor positivity (PgR 636) (p = 0.381).In Group B (tamoxifen 10 mg/day), the mean percentage of nuclei stained by Ki-67 (MIB-1) was 24.69% before and 10.43% after tamoxifen treatment. Mean percentage of nuclei stained by estrogen receptor (1D5) was 59.53% before and 25.99% after tamoxifen treatment. Mean percentage of nuclei stained by progesterone receptor (PgR 636), was 59.34 before and 29.59% after tamoxifen treatment. A statistically significant reduction was found with the three markers (p < 0.001).Tamoxifen significantly reduced monoclonal antibody Ki-67 (MIB-1), estrogen receptor (1D5) and progesterone receptor positivity (PgR 636) in the breast epithelium of carcinoma patients treated with a 10 mg dose of tamoxifen for 14 days.

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Section: Discussionsupporting

confidence: 87%

“…Studies of primary chemoprevention with tamoxifen in usual doses have generated high expectations with a 50% reduction in the relative risk for invasive carcinoma in high-risk patients [ 1 ]. Some evidence indicates that tamoxifen dose can be lowered to reduce its side-effects and retain drug efficacy [ 1 - 3 ].…”

Section: Introductionmentioning

confidence: 99%

Effects of low-dose tamoxifen on breast cancer biomarkers Ki-67, estrogen and progesterone receptors

Sousa¹,

Facina

Silva

et al. 2006

Int Semin Surg Oncol

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“…Most studies utilized only a dose of 20 mg/day of TMX to evaluate its effects on breast cancer. However, according to Facina et al (2003), 34 a dose of 10 mg/day had antiproliferative effects on the mammary epithelium adjacent to the fibroadenoma in premenopausal women. Other studies did not describe the dose of TMX administered.…”

Section: Tamoxifen Association With Other Therapiesmentioning

confidence: 99%

Impacts of Cytochrome P450 2D6 (CYP2D6) Genetic Polymorphism in Tamoxifen Therapy for Breast Cancer

Bezerra

Santos-Veloso

Bezerra

et al. 2018

Rev Bras Ginecol Obstet

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Tamoxifen (TMX) is the main drug used both in pre and postmenopausal women as adjuvant treatment for hormone receptor-positive breast cancer. An important barrier to the use of TMX is the development of drug resistance caused by molecular processes related to genetic and epigenetic mechanisms, such as the actions of cytochrome P450 2D6 (CYP2D6) polymorphisms and of its metabolites. The present study aimed to review recent findings related to the impact of CYP2D6 polymorphisms and how they can affect the results of TMX in breast cancer treatment. The keywords CYP2D6, tamoxifen, and breast cancer were searched in the PubMed, Scopus, The Cochrane Library, Scielo, and Bireme databases. Studies related to other types of neoplasms or based on other isoenzymes from cytochrome P450, but not on CYP2D6, were excluded. The impact of CYP2D6 polymorphisms in the TMX resistance mechanism remains unclear. The CYP2D6 gene seems to contribute to decreasing the efficacy of TMX, while the main mechanism responsible for therapy failure, morbidity, and mortality is the progression of the disease.

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Nonproliferative epithelial alteration and expression of estrogen receptor and Ki67 in the contralateral breast of women treated with tamoxifen for breast cancer

et al. 2007

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Efeitos de diferentes doses de tamoxifeno sobre a proliferação celular do epitélio mamário

Abstract: IntroduçãoO carcinoma de mama representa um dos principais problemas de saúde do mundo ocidental. É considerado doença complexa e multifatorial, que sofre fortes influências de fatores genéticos e ambientais. Sua incidência cresce progressiva-

Cited by 4 publications

References 20 publications

Effects of low-dose tamoxifen on breast cancer biomarkers Ki-67, estrogen and progesterone receptors

Effects of low-dose tamoxifen on breast cancer biomarkers Ki-67, estrogen and progesterone receptors

Impacts of Cytochrome P450 2D6 (CYP2D6) Genetic Polymorphism in Tamoxifen Therapy for Breast Cancer

Nonproliferative epithelial alteration and expression of estrogen receptor and Ki67 in the contralateral breast of women treated with tamoxifen for breast cancer

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