Mistaken Identifiers: Gene name errors can be introduced inadvertently when using Excel in bioinformatics If you are too lazy to get to the punchline: "MatchMiner [1] and GoMiner [2] are two bioinformatics program packages we published recently in another Biomed Central Journal, Genome Biology. When we were beta-testing those programs on microarray data, a frustrating problem occurred repeatedly: Some gene names kept bouncing back as "unknown." A little detective work revealed the reason: Use of one of the research community's most valuable and extensively applied tools for manipulation of genomic data can introduce erroneous names. A default date conversion feature in Excel (Microsoft Corp., Redmond, WA) was altering gene names that it considered to look like dates. For example, the tumor suppressor DEC1 [Deleted in Esophageal Cancer 1] [3] was being converted to '1-DEC.' Figure 1 lists 30 gene names that suffer an analogous fate."