Complex sentence: Even though humans do not have a functioning CMAH gene, Neu5Gc has been found present in normal human tissue, with larger amounts found in both fetal and cancerous tissues and studies suggest that it could be an excellent cancer cell marker.
Split into simpler sentences: Even though humans do not have a functioning CMAH gene, Neu5Gc has been found present in normal human tissue, with larger amounts found in both fetal and cancerous tissues. In fact, studies suggest that it could be an excellent cancer cell marker.