Substance playing a role in tumor metastasis cascade is

Ans is 'a' i.e. Collagenase IVVarious steps of metastasis and molecules involvedDetachment of tumor cells - Down regulation of expression of either E-cadherins or cateninsAttachement to ECM (including basement membrane) - Tumor cells express integrins that helps in the attachement.Degradation of ECM - proteolytic enzymes (most impoant proteases are metalloproteinases (MMPs) including collegenase IV).Vascular dissemination and homing of tumor cells - Among adhesion molecule CD44 is of paicular interest.