No abstract

Prevention of breast cancer can be achieved with a better understanding of the factors contributing to normal breast development. Because the breast develops postnatally, alterations in the development and lifetime activity of the neuroendocrine system may set up an environment that increases cancer risk. The present study examined how two neonatal experiences over the first 3 weeks of life influence normal and malignant mammary gland development in female BALB/c mice. Following puberty, both brief (15 minutes) and prolonged (4 hours) daily maternal separations of newborn mice accelerated mammary gland development relative to nonseparated mice. Despite similar mammary gland morphologies between mice exposed to these two neonatal separation experiences, only mice exposed to prolonged maternal separation bouts showed a higher incidence and faster onset of mammary tumorigenesis following adulthood carcinogen [7,12-dimethylbenz(a)anthracene] administration. Molecular analysis of estrogen receptor α (ERα) and p53, two proteins that have been implicated in breast cancer, revealed that for mice exposed to prolonged neonatal maternal separation bouts, mammary gland ERα protein levels were upregulated in a transcription-independent manner. On the other hand, p53 expression in mammary glands of adult mice was not differentially influenced by neonatal experiences. Our findings show that chronic, moderate psychosocial stress during the neonatal period increases the expression of ERα protein and promotes mammary tumorigenesis in adulthood. Cancer Prev Res; 3(11); 1398-408. ©2010 AACR.

A s of June 2021, there have been over 178 million cases of COVID-19 and over 3.8 million deaths worldwide. 1 The province of Ontario had recorded more than 542 000 cases and 9000 deaths in the same time period. 2 To mitigate the spread of COVID-19 and preserve health system capacity for testing and treatment of COVID-19 cases, in March 2020, the Ontario government directed health care providers to ramp down elective surgeries and nonemergent clinical activities and to cease or reduce to minimal levels all nonessential health care services. 3 On Mar. 23, 2020, Ontario Health recommended that all cancer screening services be deferred, and correspondence regarding these services was suspended. Screening services were permitted to resume on May 26, 2020, in accordance with operational public health requirements, 3 and correspondence restarted in January 2021.Among Canadian women, breast cancer is the leading incident cancer and second-leading cause of cancer death. 4 Offering women at higher risk more tailored breast screening may improve detection of breast cancer at an early stage and reduce the risk that cancer will be detected between screening examinations. Such cancers, known as interval cancers, are more likely than screen-detected cancers to have a poor prognosis. [5][6][7] The Ontario Breast Screening Program (OBSP) recommends annual mammographic screening to women aged 50 to 74 years who have certain risk factors that put them at higher than average risk of developing breast cancer. 8 As well,