To the Editor,

Liu et al. [1] in their recent article have clearly shown that matrilysin modulates the sensitivity of lung cancer cells to FasL-mediated apoptosis. The findings of Liu et al. add to the growing array of systemic malignancies in which matrilysin plays a significant etiopathogenetic role.

For instance, Luo et al. [2] have shown that matrilysin expression by rectal carcinoma cells is closely related to the Dukes stage of the tumor; thus, indicating a close relationship between tumor invasion and matrilysin expression. In fact, serum matrilysin levels can help to predict recurrence in patients with surgically treated colorectal carcinomas [3]. Similarly, high-stage renal cell carcinomas express higher levels of matrilysin in comparison to lower stage carcinomas; thus, reinforcing the etiopathogenetic role of matrilysin in tumor progression in these tumors [4]. Similarly, Itatsu et al. [5] have recently shown that matrilysin expression by cholangiocarcinomas is associated with a poor post-operative prognosis. Matrilysin also plays a significant role in disease progression in dermatologic tumors such as melanomas. In fact, increased matrilysin expression is associated with increased depth of invasion in malignant melanomas [6].

Clearly, matrilysin plays a major role in disease progression, invasion, and metastasis in almost all systemic malignancies. Matrilysin expression, thus, is a significant reflection of the prognosis in these tumors. The next few years will hopefully see the identification of appropriate molecules by means of which oncologists may be able to alter matrilysin expression for appropriate beneficial effect in the management of these systemic tumors.