MMP3 and glaucoma: In addition, Mahale et al. used the human RT2 Profiler polymerase chain reaction (PCR) array to study the differential gene expression between seven capsules of failed Ahmed glaucoma valves and two control Tenon's capsules.8 They found 39 genes with more than two-fold differential gene expression in three or more of the capsules, including CTGF, THBS1, SERPINE1, THBS2, COL3A1, MMP3, and IL1A genes.