The aim of this study is to adapt and pilot test a type of therapy called Emotion Regulation Therapy (ERT-C) for informal caregivers of patients with cancer. Informal caregivers include partners, family members, children, parents, and friends providing informal care to a patient. Providing care to someone with cancer can be difficult. The purpose of this intervention is to improve coping and physical well-being among caregivers, which in turn will allow them to provide better care for their loved ones. Investigators would also like to learn about biological factors like stress that may affect one's emotional and physical well-being. This study will allow to better understand caregivers needs, and further develop a program to provide services to caregivers within MSKCC community and nationwide.