Renee -
Our research can be a double-edged sword. I think I found the article you referred to, and it was very interesting, but also highly specific, and did not involve a study of cancer in humans.
Criteria - emphysema, lung damage sufficient to require lung resection, history of smoking (5-10 years or more) and half the group also had COPD Scientists, using tissue harvested from the lungs of 16 people. Their harvested lung tissue was implanted in the lung tissue of dead mice and studied. I was unable to figure out the amount of NAC used compared to the dosgae a human uses, and the duration of the experiment.

The study did not conclude that nobody should use NAC, rather it said... "Consequently, NAC treatment in smokers or patients with COPD, who are at increased risk of developing lung cancer and exhibit low JunD levels in lung cells, should be considered only with great caution." (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6795405/)

So, take it for what is, a limited preliminary study, with a recommendation for a limited population. If you meet their stated criteria, perhaps you should avoid NAC.

On the other hand, here is another recent article that identifies NAC as having anti-proliferative effects on a number of cancers:
https://www.nature.com/articles/s41598-023-34266-w
Sue