Section 866.6040 - Gene expression profiling test system for breast cancer prognosis(a)Identification. A gene expression profiling test system for breast cancer prognosis is a device that measures the ribonucleic acid (RNA) expression level of multiple genes and combines this information to yield a signature (pattern or classifier or index) to aid in prognosis of previously diagnosed breast cancer.(b)Classification. Class II (special controls). The special control is FDA's guidance document entitled "Class II Special Controls Guidance Document: Gene Expression Profiling Test System for Breast Cancer Prognosis." See § 866.1(e) for the availability of this guidance document. 72 FR 26291 , May 9, 2007