Cancer cells produce gelatinase B [stained by matrix metalloproteinase (MMP)-9] which digests the muscularis mucosa (MM) facilitating the progression of the malignant tissue to invade the subjacent tissues. The figure in the left highlights positive staining of MMP-9.

 
 
  Part of: Al Qudah M, Haboubi N (2022) Pitfalls in the reporting of neoplastic and pseudo neoplastic lesions in the colon and rectum. Folia Medica 64(3): 393-400. https://doi.org/10.3897/folmed.64.e68357