Cohort A: breast, prostate and colorectal cancer patients will be invited to join the study for a period of 12 weeks. If they are able to make the dates and times of the choir sessions they will become part of the experimental group. If they are unable to make the dates and times or live too far away but fulfil all the same criteria (including expressing an interest in singing) they will become part of the control group. Data collection for all participants will include (a) completing psychological scales which will be available in hard copy or as online versions; (b) providing saliva samples before 4 choir rehearsals: week 1, week 6 and week 12 with a three month follow-up (week 24). Experimental participants will be expected to attend as many of the first 12 choir sessions in the time period as possible but will then select whether they continue involvement in the choir for the following 12 weeks.