A patent specification must include a written description of the invention and a description of how to make and use the invention. In University of California v. Eli Lilly and Co. the Court of Appeals for the Federal Circuit (CAFC) affirmed a lower court decision that a patent which included claims directed to mammalian, vertebrate and human cDNA was invalid because there was no written description of the cDNA. The CAFC noted that a written description of DNA "requires a precise definition, such as by structure, formula, chemical name or physical properties". The Court stated that describing a method for preparing cDNA or describing the protein coded for by the cDNA while describing how to make and use the cDNA did not meet the written description requirement.