The basement membrane separates the epidermis from the dermis. Squamous cell carcinoma (cSSC) is cancer (tumor) that enters the dermis through this membrane. This thin, pliable platform supports cells and tissues. It also mediates complex signaling processes. Knowledge of the membrane’s proteins can reveal new insights on cSSC. This study analyses the role of such proteins in the tumor microenvironment.

The researchers studied the proteins in the tumor environment to understand invasive and inflammatory activities. The focus is on laminin chain protein loss and cellular swelling, and the researchers examined the α3, β3, and γ2 proteins in-depth using patient tumor samples. The study used techniques like immunohistochemistry, shRNA knockdown, RNA sequencing, and mouse xenograft models.

 The tumor analysis using laminin-specific antibodies identified a link. It associated poorly differentiated SCC with reduced Laminin α3 expression. There was no other link with other subunits. The tumor invasion increased in vitro and in vivo due to laminin α3 loss. It was true of both xenografted and patient tumor samples. Staining and Western blot linked the loss of laminin α3 with pMLC increase. The protein’s invasive potential decreased due to inhibited ROCK, but not RAC-1. The loss of γ2 increased monocyte recruitment in the tumor microenvironment.

The data provides evidence linking cSCC with laminin α3 loss. This decrease aggravates tumors due to the impact of epithelial and immune components.