Data from the National Institute on Drug Abuse (NIDA) and the Centers for Disease Control and Prevention (CDC) reveal high numbers of adolescent substance use in the United States. Substance use among adolescents can lead to increased risk of transmission of sexually transmitted infections, vehicular fatalities, juvenile delinquency, and other problems associated with physical and mental health. Adolescents are particularly susceptible to involvement in substance use due to the underdeveloped state of the adolescent brain, which can lead to reduced decision-making ability and increased long-term effects of drugs and alcohol. Understanding the causes of adolescent substance use is vital for successful prevention and intervention programs.

Retroviruses, a form of mobile genetic elements, have important roles in disease and primate evolution. Exogenous retroviruses, such as human immunodeficiency virus (HIV), have significant pathological implications that have created a massive public health challenge in recent years. Endogenous retroviruses (ERVs), which are the primary focus of this review, can also be pathogenic, as well as being beneficial to a host in some cases. Furthermore, retroviruses may have played a key role in primate evolution that resulted in the incorporation of these elements into the human genome. Retroviruses are mobile genetic elements that have important roles in disease and primate evolution. We will further discuss the pathogenic potential of retroviruses, including their role in cancer biology, and will briefly summarize their evolutionary implications.

Breast cancer is a leading cause of cancer death in the world. The triple-negative breast cancer subtype is associated with poorer prognosis than hormone receptor-positive subtypes and is more prevalent among African Americans than white, European Americans. The goal of this study has been to elucidate environmental, hormonal, and cultural factors that may be contributing to this disparity in an effort to identify modifiable risk factors and improve triple-negative breast cancer outcomes. Factors that may impact risk include vitamin D defiency, hormonal factors, environmental and dietary exposure, radiation exposure, and obesity. These factors may disproportionately affect African American women as a result of socioeconomic status, lifestyle, and cultural norms. Furthermore, disparities in prognosis may be compounded by barriers such as access to healthcare, prevention education, and perceptions of healthcare. Both biological and sociocultural factors impacting risk must be addressed in order for future prevention and treatment efforts to succeed.