Related Experiment Video
Updated: Jan 21, 2026
09:36
Changes in Mammary Gland Morphology and Breast Cancer Risk in Rats
Published on: October 16, 2010
30.2K
Oral Contraceptive Use and Breast Cancer Risk: Retrospective and Prospective Analyses From a BRCA1 and BRCA2 Mutation
Lieske H Schrijver1, Håkan Olsson2, Kelly-Anne Phillips3,4,5
1Department of Epidemiology, Netherlands Cancer Institute, Amsterdam, the Netherlands.
JNCI Cancer Spectrum
|July 31, 2019
Summary
Oral contraceptive preparation (OCP) use may increase breast cancer (BC) risk in BRCA2 mutation carriers, but findings are inconsistent for BRCA1 carriers. Further research is needed to clarify the association between OCP use and BC risk in these populations.
Area of Science:
- Oncology
- Genetics
- Epidemiology
Background:
- The relationship between oral contraceptive preparation (OCP) use and breast cancer (BC) risk remains unclear for individuals carrying BRCA1 and BRCA2 mutations.
- BRCA1 and BRCA2 mutations are associated with a significantly increased lifetime risk of developing breast cancer.
Purpose of the Study:
- To investigate the association between oral contraceptive preparation (OCP) use and breast cancer (BC) risk in BRCA1 and BRCA2 mutation carriers.
- To evaluate potential differences in BC risk based on the type of analysis (prospective vs. retrospective) and duration of OCP use.
Main Methods:
- Utilized data from 6030 BRCA1 and 3809 BRCA2 mutation carriers.
- Employed age-dependent Cox regression models, stratified by study and birth cohort.
- Conducted prospective, left-truncated retrospective, and full-cohort retrospective analyses.
Main Results:
- For BRCA1 carriers, prospective analyses showed no association with BC risk, while retrospective analyses indicated a 26-51% increased risk.
- For BRCA2 carriers, prospective analyses revealed a 75% increased BC risk, but retrospective analyses yielded inconsistent results.
- Evidence suggested an increased risk with longer OCP duration, particularly before the first full-term pregnancy for both BRCA1 and BRCA2 carriers.
Conclusions:
- Prospective analyses did not link past OCP use to increased BC risk in BRCA1 carriers aged 40-50.
- A causal association between OCP use and BC risk is unlikely in BRCA2 carriers at these ages.
- Inconsistencies between prospective and retrospective analyses highlight potential survival bias or a true association in younger women; nonhormonal contraception is recommended for BRCA1/2 carriers.
Related Concept Videos
01:24Electron Carriers
91.5K
Electron carriers can be thought of as electron shuttles. These compounds can easily accept electrons (i.e., be reduced) or lose them (i.e., be oxidized). They play an essential role in energy production because cellular respiration is contingent on the flow of electrons.
Over the many stages of cellular respiration, glucose breaks down into carbon dioxide and water. Electron carriers pick up electrons lost by glucose in these reactions, temporarily storing and releasing them into the electron...
Over the many stages of cellular respiration, glucose breaks down into carbon dioxide and water. Electron carriers pick up electrons lost by glucose in these reactions, temporarily storing and releasing them into the electron...
91.5K
01:39Mutations
94.4K
Overview
94.4K
01:35Mutations
43.8K
Mutations are changes in the sequence of DNA. These changes can occur spontaneously or they can be induced by exposure to environmental factors. Mutations can be characterized in a number of different ways: whether and how they alter the amino acid sequence of the protein, whether they occur over a small or large area of DNA, and whether they occur in somatic cells or germline cells.
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
43.8K
02:21Cancers Originate from Somatic Mutations in a Single Cell
14.6K
Cancer arises from mutations in the critical genes that allow healthy cells to escape cell cycle regulation and acquire the ability to proliferate indefinitely. Though originating from a single mutation event in one of the originator cells, cancer progresses when the mutant cell lines continue to gain more and more mutations, and finally, become malignant. For example, chronic myelogenous leukemia (CML) develops initially as a non-lethal increase in white blood cells, which progressively...
14.6K
00:36Viral Mutations
39.8K
A mutation is a change in the sequence of bases of DNA or RNA in a genome. Some mutations occur during replication of the genome due to errors made by the polymerase enzymes that replicate DNA or RNA. Unlike DNA polymerase, RNA polymerase is prone to errors because it is not capable of “proofreading” its work. Viruses with RNA-based genomes, like HIV, therefore accrue mutations faster than viruses with DNA-based genomes. Because mutation and recombination provide the raw material...
39.8K
01:21Carrier Transport
925
The generation of electrical current in semiconductors is fundamentally driven by two mechanisms: drift and diffusion. These processes are essential for the functionality and performance of semiconductor-based devices.
Drift Current:
The drift of charge carriers is started by an external electric field (E). Charged particles, such as electrons and holes, experience an acceleration between collisions with lattice atoms. For electrons, this results in a drift velocity (vd) given by:
Drift Current:
The drift of charge carriers is started by an external electric field (E). Charged particles, such as electrons and holes, experience an acceleration between collisions with lattice atoms. For electrons, this results in a drift velocity (vd) given by:
925