Breast cancer therapy for BRCA1 carriers: moving towards platinum standard?

An overview of the research progress of BRCA gene mutations in breast cancer

The breast cancer susceptibility gene (BRCA) is an important tumor suppressor gene, including BRCA1 and BRCA2, a biomarker that assesses the risk of breast cancer and influences a patient's individualized treatment options. BRCA1/2 mutation (BRCAm) increases the risk of breast cancer. However, breast-conserving surgery is still an option for BRCAm, and prophylactic mastectomy and nipple-sparing mastectomy may also reduce the risk of breast cancer. BRCAm is sensitive to Poly (ADP-ribose) polymerase inhibitor (PARPi) therapy due to specific types of DNA repair defects, and its combination with other DNA damage pathway inhibitors and endocrine therapy and immunotherapy are also used for the treatment of BRCAm breast cancer. The current treatment and research progress of BRCA1/2 mutant breast cancer in this review provides a basis for the individualized treatment of patients with this type of breast cancer.

Systemic treatment for hereditary cancers: a 2012 update

The history of specific therapy for hereditary tumors dates back to mid 1980s and involves a number of reports demonstrating regression of familial colon polyps upon administration of sulindac. Virtually no clinical studies on other hereditary cancer types were available until the year 2009, when Byrski et al. presented the data on unprecedented sensitivity of BRCA1-associated breast malignancies to cisplatin. This breakthrough has revived interest to the treatment of cancer in germ-line mutation carriers. Recent trials and clinical observations have confirmed the efficacy of platinating agents and PARP inhibitors in BRCA1/2-driven breast, ovarian and pancreatic carcinomas. Pegylated liposomal doxorubicin may be considered as a promising treatment option for BRCA1/2-related ovarian cancer after the failure of platinum-containing therapy. Several novel drugs have been recently introduced in the management of rare familial tumor syndromes. Vandetanib, a low-molecular weight RET kinase inhibitor, demonstrated substantial efficacy in the treatment of hereditary and sporadic medullary thyroid cancer. Vismodegib, an inhibitor of SMO oncoprotein, caused regression of basal-cell carcinomas in patients with Gorlin syndrome. Down-regulation of mTOR kinase by everolimus has been successfully used for the therapy of subependymal giant-cell astrocytomas in patients with tuberous sclerosis. The achievements in the prevention, diagnostics and treatment of hereditary cancers may serve as an excellent example of triumph of translational medicine.

Platinum resistance in breast and ovarian cancer cell lines

Breast and ovarian cancers are among the 10 leading cancer types in females with mortalities of 15% and 6%, respectively. Despite tremendous efforts to conquer malignant diseases, the war on cancer declared by Richard Nixon four decades ago seems to be lost. Approximately 21,800 women in the US will be diagnosed with ovarian cancer in 2011. Therefore, its incidence is relatively low compared to breast cancer with 207.090 prognosed cases in 2011. However, overall survival unmasks ovarian cancer as the most deadly gynecological neoplasia. Platinum-based chemotherapy is emerging as an upcoming treatment modality especially in triple negative breast cancer. However, in ovarian cancer Platinum-complexes for a long time are established as first line treatment. Emergence of a resistant phenotype is a major hurdle in curative cancer therapy approaches and many scientists around the world are focussing on this issue. This review covers new findings in this field during the past decade.

Drug therapy for hereditary cancers

Tumors arising in patients with hereditary cancer syndromes may have distinct drug sensitivity as compared to their sporadic counterparts. Breast and ovarian neoplasms from BRCA1 or BRCA2 mutation carriers are characterized by deficient homologous recombination (HR) of DNA, that makes them particularly sensitive to platinum compounds or inhibitors of poly (ADP-ribose) polymerase (PARP). Outstandingly durable complete responses to high dose chemotherapy have been observed in several cases of BRCA-related metastatic breast cancer (BC). Multiple lines of evidence indicate that women with BRCA1-related BC may derive less benefit from taxane-based treatment than other categories of BC patients. There is virtually no reports directly assessing drug response in hereditary colorectal cancer (CRC) patients; studies involving non-selected (i.e., both sporadic and hereditary) CRC with high-level microsatellite instability (MSI-H) suggest therapeutic advantage of irinotecan. Celecoxib has been approved for the treatment of familial adenomatous polyposis (FAP). Hereditary medullary thyroid cancers (MTC) have been shown to be highly responsive to a multitargeted tyrosine kinase inhibitor vandetanib, which exerts specific activity towards mutated RET receptor. Given the rapidly improving accessibility of DNA analysis, it is foreseen that the potential predictive value of cancer-associated germ-line mutations will be increasingly considered in the future studies.

Gemcitabine and cisplatin salvage regimen in heavily pretreated metastatic breast cancer: a Brazilian experience

Gemcitabine and cisplatin combination (Gem-Cis) is a commonly used regimen in metastatic breast cancer (MBC), with proven activity in phase II trials. It is mostly used as a salvage regimen for progressive disease refractory to anthracyclines and taxanes, and when liver dysfunction secondary to liver metastasis precludes these drugs. Retrospective review of medical charts was conducted for patients treated with Gem-Cis for MBC in a single institution in Brazil between January 2004 and July 2007. The purpose of this study was to evaluate the outcomes and toxicity of Gem-Cis in a broad indication, including patients with deteriorated performance status (PS) and liver dysfunction, which were excluded from clinical trials. Fifty-six patients were included. Median age was 52 years, 46.4% were hormone-receptor negative, 57.2% received 3 or more prior chemotherapy lines, and 34 had liver metastasis. The median overall survival (OS) was 7.6 months, the median progression-free survival was 3.3 months, and the response rate was 21.2%. In variable analysis, PS was significantly associated with OS, even after adjusting to other factors. Toxicities included grades 3 or 4 anemia in 19.3%, neutropenia in 21.1%, and thrombocytopenia in 12.3%. Gem-Cis was a relatively active combination in this population that typically carries a poor prognosis. The subgroup of patients with favorable PS experienced longer survival, even when liver metastasis and hepatic dysfunction were a concern. Toxicity was manageable and it was not correlated with PS or liver dysfunction.

Founder BRCA1/2 mutations in the Europe: implications for hereditary breast-ovarian cancer prevention and control

Detection of mutations in hereditary breast and ovarian cancer-related BRCA1 and BRCA2 genes is an effective method of cancer prevention and early detection. Different ethnic and geographical regions have different BRCA1 and BRCA2 mutation spectrum and prevalence. Along with the emerging targeted therapy, demand and uptake for rapid BRCA1/2 mutations testing will increase in a near future. However, current patients selection and genetic testing strategies in most countries impose significant lag in this practice. The knowledge of the genetic structure of particular populations is important for the developing of effective screening protocol and may provide more efficient approach for the individualization of genetic testing. Elucidating of founder effect in BRCA1/2 genes can have an impact on the management of hereditary cancer families on a national and international healthcare system level, making genetic testing more affordable and cost-effective. The purpose of this review is to summarize current evidence about the BRCA1/2 founder mutations diversity in European populations.