Hey! My job consists of shift work. I currently work nights. 
I did that once when I worked at Walmart
Yeah, I actually didn't know that women who work shift work have a higher chance for breast cancer. 
Is that true?  Wow!  How did they figure that out
I'm not entirely sure since there are so many contributors to breast cancer. I'm sure it has to do with epidemiology. 
You think Night work increases Stress and that may exacerbate cancer indicators?
It might be. Shift work also increases diabetes risks as well. Especially in men.