Investigation of tissue inhibitor of metalloproteinases 1 in plasma from colorectal cancer patients and blood donors by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry.

Early detection of colorectal cancer (CRC) improves patient survival. Plasma tissue inhibitor of metalloproteinases 1 (TIMP-1) measurements by enzyme-linked immunosorbent assay (ELISA) have been suggested as a new method for the early detection of CRC. To further investigate the nature of TIMP-1 in plasma, surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI TOF MS) was used. TIMP-1 measurements of plasma from 16 healthy donors and 14 CRC patients were performed using TIMP-1 monoclonal antibody in SELDI TOF MS and ELISA. SELDI TOF MS applying an antibody to TIMP-1 revealed that human plasma TIMP-1 has a mass of 25.1 kDa and exhibits several isoforms. Both methods showed increased plasma TIMP-1 values for cancer patients as compared to healthy individuals. The p values for the separation of the groups were 0.0019 for ELISA and <0.0001 for SELDI TOF MS. CRC did not fundamentally affect the appearance of TIMP-1 as evaluated by SELDI TOF MS.

Tissue inhibitor of metalloproteinases-1 in breast cancer.

Whether patients diagnosed with primary breast cancer are offered adjuvant systemic therapy following surgical removal of the tumor is based on prognosis. Prognosis is estimated in every patient using established prognostic variables. Unfortunately, when using the currently available prognostic parameters a significant proportion of patients are over-treated. Thus, in order to improve stratification of breast cancer patients, additional prognostic factors need to be identified. Tissue inhibitor of metalloproteinases-1 (TIMP-1) is one of the promising candidates for new prognostic markers in breast cancer, as a number of studies have demonstrated an association between high tumor-tissue levels of TIMP-1 mRNA as well as TIMP-1 protein and a poor prognosis of breast cancer patients. TIMP-1 is a member of the TIMP family, currently comprising four members (TIMP-1-4), and its main function is inhibition of the activity of various matrix metalloproteinases (MMPs). The association between high levels of protease inhibitor and poor prognosis may be somewhat surprising, as proteolytic activity plays a pivotal role in cancer cell invasion and metastasis. However, the recent discovery of other biological functions of TIMP-1 such as growth-stimulating functions, as well as anti-apoptotic and pro-angiogenetic effects, may in part explain this paradox. The purpose of this review is to give an update on the current status of TIMP-1 in breast cancer, emphasizing the prognostic utility of the inhibitor. In addition, the suggested tumor-stimulatory roles of TIMP-1 will be outlined.

Evaluation of sample handling in relation to levels of tissue inhibitor of metalloproteinases-1 measured in blood by immunoassay.

BACKGROUND: The possible effect of preanalytical conditions such as blood sample preparation and handling on TIMP-1 levels in blood needs thorough investigation. MATERIALS AND METHODS: Blood was collected in dry tubes and tubes containing EDTA and kept at 4 degrees C or 20 degrees C for 1, 3, 8, 24 or 72 hours before processing into serum or EDTA plasma. In addition, serum and EDTA plasma samples were frozen and thawed 1-8 times. TIMP-1 was measured by ELISA. RESULTS: Time to processing for up to 72 hours did not significantly affect TIMP-1 levels in serum. In EDTA plasma, TIMP-1 levels were stable for up to eight hours; however, if samples were kept for 24 hours or longer the TIMP-1 levels increased (p < 0.0001). Repeated freezing and thawing had a significant effect on TIMP-1 levels in serum (p = 0.04). In plasma, repeated freezing and thawing for up to six times did not influence TIMP-1. However, in plasma samples exposed to seven or eight freeze/thaw cycles TIMP-1 levels decreased, although not significantly (p = 0.23). CONCLUSIONS: Handling and processing of blood samples is crucial for TIMP-1 measurement by immunoassay. In serum, TIMP-1 levels are unaffected by time to processing. Plasma samples should be processed within eight hours to avoid a TIMP-1 increase. For the measurement of TIMP-1 in archival material, serum should not be used because TIMP-1 levels are significantly affected by repeated freezing and thawing; archival plasma can readily be used provided that samples have not been frozen and thawed more than six times.