1. Department of Immunology and Rheumatology. Instituto Nacional de Ciencias Médicas y Nutrición Salvador-Zubirán (INCMyN-SZ), Mexico City, Mexico
2. Department of Psychiatry. Instituto Nacional de Ciencias Médicas y Nutrición Salvador-Zubirán (INCMyN-SZ, Mexico City, Mexico
3. Palliative care service, Instituto Nacional de Cancerología, México City, México
4. Department of Neurology and Psychiatry, University of Manitoba, Cancer Care Manitoba, Winnipeg, Canada.