A macrophage migration inhibitory factor (MIF), originally described as a product of activated lymphocytes, has been defined as a 12 kDa protein, expressed in a wide variety of tissues. Here MIF is identified as a phenylpyruvate tautomerase (EC 5.3.2.1) having /»-hydroxyphenylpyruvate and phenylpyruvate as its natural substrates. The definition of MIF as an enzyme may yield insight into the mechanism of action of this proinflammatory and immunomodulating cytokine.

We used nested reverse transcriptase PCR to investigate the expression of the FHIT gene, a presumptive tumor suppressor gene located in chromosomal band 3p14.2, in non‐neoplastic samples. Multiple transcripts of the FHIT gene were found in peripheral blood lymphocytes, skeletal muscle, and liver of healthy individuals, as well as in a cell line derived from synovial tissue. The data indicate that variable splicing of the FHIT transcript, leading to deletions of exons and thus anomalous or absent FHIT protein production, occurs frequently in non‐neoplastic tissues. Hence, the finding of multiple nonfunctional FHIT transcripts is not tumor‐specific and cannot be used as a genetic marker of neoplasia. Genes Chromosom. Cancer 19:215–219, 1997. © 1997 Wiley‐Liss, Inc.

No abstract