cell adhesion in pathology

Does it suggest here that decreased expression of adhesion molecules leads to loss of adhesion and also invasion of basement membrane and migration? How does it lead to invasion of basement membrane and migration though? I thought an increase in expression of adhesion molecules would lead to invasion of basement membrane and migration.

Would really like any views on this!

Cancers that arise from epithelial (i.e. surface) tissues are known as carcinomas and are the most common types of cancer. As the diagram shows, epithelial cells acquire various mutations causing them to proliferate out of control. However, in order for these cells to become malignant, they must be able to separate from the surrounding tissue - they do this by downregulating the production of adhesion molecules such as E-cadherin, again by acquiring mutations. This process is known as epithelial to mesenchymal transition (EMT). Once they lose these adhesion molecules, the cells can migrate into the bloodstream and spread to various other parts of the body - known as metastasis. They also need to produce proteins which breakdown the extracellular matrix and the basement membrane to become invasive - examples of these enzymes are matrix metalloproteinases (MMPs). You're right though, in order to invade the basement membrane of distant tissues and metastasise they must increase the expression of other adhesion molecules in order to adhere to the blood vessels and the basement membrane of these tissues - as the diagram states, one of these adhesion molecules is N-cadherin (different from E-cadherin).