• I think It means directed "to all". For instance a pan-cadherin antibody recognizes all cadherins without differentiating among subtypes. 

Dear Hassanshahi,

As Dupraz said, pan means "all". For example, pancytokeratin (marker of epithelial cells)- means all keratins expressed on epithelial cells,  pancaspase inhibitor (like z-VAD-fmk)-means inhibitor of all caspases.

Regards

The prefix "pan" normally relates to an antibody directed to a type of cell independently from its sub type or localization. Thus, pan endothelial cell marker is an antibody able to recognize all the endothelial cells regardless their subtypes, a pan-cytokeratin marker is directed to all the cytokeratins togheter, a pan-T-cell marker recognizes all the T lymphocytes regardless their types and antigen expression. 

Thank you all for your comments. I really appreciate it 

Although pan is ment for all in many cases the antibody coctails do not include all of them. For example pan-keratin antibodies are against many types of keratins and not really all of them. So one has to go through the data sheath and see which amtibodies are included. For example sarcomatoid carcinomas may be negative with pankeratin but may be