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Influence of treatment with tamoxifen and change in tumor burden on the IGF‐system in breast cancer patients
Author(s) -
Helle Svein I.,
Holly Jeff M. P.,
Tally Michael,
Hall Kerstin,
Stappes Jos Van Der,
Lonning Per E.
Publication year - 1996
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/(sici)1097-0215(19960822)69:4<335::aid-ijc17>3.0.co;2-4
Subject(s) - tamoxifen , breast cancer , medicine , mammary gland , oncology , antiestrogen , chemotherapy , endocrinology , urology , cancer , gastroenterology
Plasma levels of IGF‐I IGFBP‐I and IGFBP‐3 were measured before and during treatment with tamoxifen up to 19 + months in 34 post‐menopausal patients with advanced breast cancer. In 28 patients, pro‐IGF‐IIE (IGF‐IIE) levels were determined and IGFBP‐3 was evaluated by immunoblot in 27 patients. Tamoxifen suppressed plasma levels of IGF‐I by a mean value of 25.5%–37.7% at different times. This effect was fully developed after 1ndash;2 months of treatment. IGF‐IIE was decreased by a mean value of 7.7–23.2% at different time intervals during treatment with tamoxifen, but this effect was significant after long‐term treatment (19 months +) only. Plasma IGFBP‐I increased by a mean value varying between 48.6% and 190.1%. Tamoxifen had no significant effect on total IGFBP‐3 levels. However, patients responding to treatment had a 28% reduction in fragmentation of IGFBP‐3, while patients with progressive disease had a 36% increase in fragmentation. The difference between responders and non‐responders was highly significant. These findings confirm and extend previous observations regarding the effects of treatment with tamoxifen on IGF‐I and IGFBP‐I. The finding that patients responding to tamoxifen achieve a reduction in the ratio of fragmented to intact IGFBP‐3 while patients progressing on therapy experience an increase in the IGFBP‐3 fragmentation ratio, suggest that the tumor burden influences IGFBP‐3 protease activity in breast‐cancer patients. © 1996 Wiley‐Liss, Inc.