Matrix metalloproteinases (MMPs) are a major group of enzymes that regulate cell-matrix composition. MMP genes show a highly conserved modular structure. Ample evidence exists on the role of MMPs in normal and pathological processes, including embryogenesis, wound healing, inflammation, arthritis, cardiovascular diseases, pulmonary diseases and cancer. The expression patterns of MMPs have interesting implications for the use of MMP inhibitors as therapeutic agents. Insights might be gained as to the preference for a general MMP inhibitor as opposed to an inhibitor designed to be specific for certain MMP family members as it relates to a defined disease state, and may give clues to potential side effects. The signalling pathways that lead to induction of expression of MMPs are still incompletely understood, but certain patterns are beginning to emerge. Regarding inhibition of MMP expression at the level of kinase pathways, it is possible that selective chemical inhibitors for distinct signalling pathways (e.g. MAPK, PKC) will hopefully, soon be available for initial clinical trials. Overexpression of selective dual specificity MAPK phosphatases have been shown to prevent MMP promoter activation which could also be used as a novel strategy to prevent activation of AP-1 and ETS transcription factors and MMP promoters in vivo. Interactions between members of different transcription factors provide fine-tuning of the transcriptional regulation of MMP promoter activity. MMPs play a crucial role in tumor invasion. Although the expression of MMPs in malignancies has been studied widely, the specific role of distinct MMPs in the progression of cancer may be more complex than has been assumed. For example, it has recently been shown that MMP-3, MMP-7, MMP-9 and MMP-12 can generate angiostatin from plasminogen, indicating that their expression in peritumoral area may in fact serve to limit angiogenesis and thereby inhibit tumor growth and invasion. The recent view about the role of stromal cells in the progression of cancer cell growth and metastasis is particularly interesting, and additional studies about the regulation of MMP gene expression and activity in malignancies are needed to understand the role and regulation of MMPs in tumor cell invasion.

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Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome, is also known as drug induced hypersensitivity syndrome and by various other names. It is now recognised as one of the severe cutaneous adverse reaction (SCAR) and can be potentially life-threatening. Historically, it was most frequently linked with phenytoin and was initially described as phenytoin hypersensitivity syndrome. However, it was later found to be caused by various other medications. Anticonvulsants and sulfonamides are the most common offender. Characteristically DRESS has a latent period of 2 to 6 weeks. The pathophysiology remains incompletely understood but involves reactivation of viruses and activation of lymphocyte. It is manifested most commonly with a morbilliform cutaneous eruption with fever and lymphadenopathy. The severity of this syndrome is related to the systemic involvement, which can result in multi-organ failure. Most important step in the management of DRESS is early diagnosis and immediate cessation of the suspected offending drug. Patients of DRESS syndrome should be managed in an intensive care set up for appropriate supportive care and infection control. Topical corticosteroids can give symptomatic relief, but systemic therapy with steroid and other immunosuppressant is usually required.