Project Summary. Little is known about grief in breast cancer (BC) patients that have experience losses associated to the cancer diagnosis, and which are the protective factors that could manage grief preventing complications such as Major Depression Disorder (MDD). Grief is a psychological phenomenon, related to MDD, which is experienced after the death of a loved one, and some literature argues that it could be also experienced after a non-death-related loss. Women diagnosed with BC experience several losses which stem from the BC diagnosis that could be potential predictors of grief and depression. Literature shows that in BC patients’ loss of social support leads to depression symptoms onset, and symbolic losses, such as sexual dysfunction, and hair loss leads to emotional distress. The affective neuroscience field has shown that grief is one of the seven primary emotions in our brain, which main function is to maintain social bonds as they convey security. According to animal models, the PANIC/GRIEF’s neurological pathway (system) is triggered by social separation, causing despair, and sustained activation of PANIC/GRIEF leads to inhibition of the seeking-reward system triggering depression symptoms. On the other hand, the social signal transduction theory of depression hypothesizes that interpersonal adversity can up-regulate components of the immune system involved in inflammation processes eliciting changes in behavior associate with initiation of depression symptoms. Literature shows that grief can activate the HPA axis resulting in increased expression of inflammation markers associated with MDD and BC progression. Grief has been widely studied in the context of death of a loved one, however, studies concerning non-death-related losses and grief have been conducted using models that show poor consistency highlighting the need for an empirical approach. The inability to cope with different types of perceived non-death-related losses could imply concerning health repercussions in BC patients. Understating the relationship between losses, grief, and depression, as well as potential protective factors is key for improving quality of life in BC patients as it this information can contribute to targeted psychological treatments. The central hypothesis of this administrative supplement is that emotion regulation and social support are potential protective coping mechanisms in grief management, depression symptoms, and upregulation of proinflammatory factors assorted to BC tumor progression after non-death-related losses. The overall goal of this study is to investigate non-death- related losses due to the BC diagnosis in relation to grief, and to determine the potential role of emotional regulation and social support as protective factors against systemic inflammation upregulation, and depression symptoms in Latina BC patients. Aim 1 will determine the relationship of perceived non-death-related losses due to breast cancer diagnosis with the e...