Substance playing a role in tumor metastasis cascade is

Substance playing a role in tumor
metastasis cascade is
a) Collagenase IV
b) TNF-alpha
c) CD99
d) NM23

Correct Answer - A
Ans is ‘a’ i.e. Collagenase IV
Various steps of metastasis and molecules involved

  1. Detachment of tumor cells - Down regulation of expression of either
    E-cadherins or catenins
  2. Attachement to ECM (including basement membrane) - Tumor cells
    express integrins that helps in the attachement.
  3. Degradation of ECM - proteolytic enzymes (most important
    proteases are metalloproteinases (MMPs) including collegenase IV).
  4. Vascular dissemination and homing of tumor cells - Among adhesion
    molecule CD44 is of particular interest.