Inhibition of Abl tyrosine kinase enhances nerve growth factor-mediated signaling in Bcr-Abl transformed cells via the alteration of signaling complex and the receptor turnover.

Receptor tyrosine kinase-mediated signaling is tightly regulated by a number of cytoplasmic signaling molecules. In this report, we show that Bcr-Abl transformed chronic myelogenous leukemia (CML) cell lines, K562 and Meg-01, express the receptor for nerve growth factor (NGF), TrkA, on the cell surface; however, the NGF-mediated signal is not particularly strong. Treatment with imatinib, a potent inhibitor of Bcr-Abl tyrosine kinase, downmodulates phosphorylation of downstream molecules. Upon stimulation with NGF, Erk and Akt are phosphorylated to a much greater degree in imatinib-treated cells than in untreated cells. Knockdown of expression of Bcr-Abl using small interfering RNA technique also enhanced NGF-mediated Akt phosphorylation, indicating that Bcr-Abl kinase modifies NGF signaling directly. Imatinib treatment also enhanced NGF signaling in rat adrenal pheochromocytoma cell line PC12 that expresses TrkA and c-Abl, suggesting that it is not only restoration of responsiveness to NGF after blocking oncoprotein activity, but also c-Abl tyrosine kinase per se may be a negative regulator of growth factor signaling. Furthermore, inhibition of Abl tyrosine kinase enhanced clearance of surface TrkA after NGF treatment and simultaneously enhanced NGF-mediated signaling, suggesting that as in neuronal cells 'signaling endosomes' are formed in hematopoietic cells. To examine the role of TrkA in CML cells, we studied cell growth or colony formation in the presence or absence of imatinib with or without NGF. We found that NGF treatment induces cell survival in imatinib-treated CML cell lines, as well as colony formation of primary CD34+ CML cells, strongly suggesting that NGF/TrkA signaling contributes to aberrant signaling in CML.

Unsupervised proteome analysis of human leukaemia cells identifies the Valosin-containing protein as a putative marker for glucocorticoid resistance.

The response to initial glucocorticoid therapy in childhood acute lymphoblastic leukaemia (ALL) reliably predicts the response to multiagent chemotherapy. Patients resistant to glucocorticoids (prednisone poor responders (PPR)) have a poorer event-free survival compared to glucocorticoid-sensitive patients (prednisone good responders (PGR)). A case-control study was performed to investigate differential protein expression in leukaemic blasts from PGR and PPR childhood ALL patients. Two-dimensional gel electrophoresis (2-DE) was used for an unsupervised screening and surface enhanced laser desorption/ionisation-time of flight mass spectrometry (SELDI-TOF MS) for the characterisation of protein spots. In difference maps of average gels for the proteomes of each responder group, differentially expressed proteins were identified after tryptic digestion and spotting onto H4-SELDI-TOF-MS chips. Proteins overexpressed in PPR were Catalase, RING finger protein 22 alpha, Valosin-containing protein (VCP) and a G-protein-coupled receptor. Proteins overexpressed in PGR were protein kinase C and malate dehydrogenase. Valosin-containing protein was chosen for validation and quantification by Western blot analysis in a second case-control group of ALL patients. In this second independent cohort, median VCP expression (P25-P75) was 0.15 (0.11-0.28) in PGR and 0.34 (0.14-0.99) in PPR patients (P = 0.04). We conclude that high VCP expression is associated with poor prednisone response in childhood ALL patients.

Investigating four 'myths' surrounding dysphagia in patients with metastatic esophageal cancer. A multi-institutional study from the North Central Cancer Treatment Group.

Eighty-five to 95% of esophageal cancer patients suffer dysphagia. Yet, few studies have focused on this symptom, and four 'myths' persist: (i) dysphagia cannot be measured; (ii) chemotherapy cannot palliate it; (iii) dysphagia predicts a poor prognosis; (iv) dysphagia is associated with a frustratingly insatiable appetite. Forty-four patients with metastatic esophageal cancer participated in this quality of life/translational component of a previously reported clinical trial. All were monitored for chemotherapy efficacy and toxicity and completed questionnaires on dysphagia and appetite at baseline and every 6 weeks. The appetite hormones, leptin and neuropeptide y, were also assessed. Forty-five per cent of patients could easily swallow solid foods; all others had varying dysphagia, thus enabling exploration of these four 'myths.' First, a single-item visual analog scale (Swallowing Scale), demonstrated excellent agreement with a previously validated questionnaire (81% at baseline), thus reminding us that dysphagia is measurable. Second, chemotherapy was associated with a trend towards improved dysphagia (P = 0.059). Third, dysphagia did not predict tumor response or survival. Fourth, dysphagia was not associated with appetite, leptin or neuropeptide y. This study helps to dispel these four 'myths' and underscores the need for further quality of life research on dysphagia.

Expression of heat-shock protein 90 in glucocorticoid-sensitive and -resistant childhood acute lymphoblastic leukaemia.

Early reduction of leukaemic cells by chemotherapy is a strong predictor for treatment outcome in childhood acute lymphoblastic leukaemia (ALL). In ALL-(Berlin-Frankfurt-Münster) trials, early treatment response is assessed by the in vivo response to glucocorticoids (prednisone response, PR), the molecular background of which is unknown. The intracellular effects of glucocorticoids (GCs) are mediated by the glucocorticoid receptor (GR). In the absence of GC, the inactive GR resides within a multiprotein complex, consisting predominantly of the chaperone protein hsp90 (heat-shock protein 90). Until now, studies targeting GC resistance mainly focused on GR disorders and alterations of genes known to be associated with drug resistance. In addition, the GR multiprotein complex was associated with GC resistance in in vitro studies. We performed a case-control study for PR to investigate the association of in vivo GC resistance and hsp90 expression in childhood ALL. Hsp90 expression was assessed using a real-time PCR approach (Taqman technology) and Western blot technology. In this setting, we found no association of in vivo GC resistance and hsp90 expression. Therefore, we conclude that the expression of hsp90, the major component of the GR activating complex, is of minor importance for the in vivo GC resistance in childhood ALL.

Chronic myelogenous leukemia blast cell proliferation is inhibited by peptides that disrupt Grb2-SoS complexes.

Chronic myelogenous leukemia (CML) is commonly characterized by the presence of the p210(Bcr-Abl) oncoprotein. Many downstream effectors of Bcr-Abl have been described, including activation of the Grb2-SoS-Ras-MAP kinase (Erk) pathway. The precise contributions of these signal-transduction proteins in CML blast cells in human patients are not yet well defined. To gain further insight into the importance of Grb2 for CML, peptides that disrupt Grb2-SoS complexes were tested. These high-affinity Grb2-binding peptides (HAGBPs) can autonomously shuttle into cells and function by binding to the N-terminal SH3 domain of Grb2. The HAGBPs were analyzed for their effects on Bcr-Abl-expressing cell lines and freshly isolated CML blast cells from patients. They induced a dramatic decrease in the proliferation of CML cell lines. This was not observed with point-mutated control peptides with abolished Grb2SH3(N) binding. As expected, Grb2-SoS complexes were greatly diminished in the HAGBP-treated cells, and MAP kinase activity was significantly reduced as determined by an activation-specific phospho-MAPK antibody. Furthermore, cell fractions that are enriched for blast cells from CML patients with active disease were also incubated with the Grb2 blocker peptides. The HAGBPs led to a significant proliferation reduction of these cells in the majority of the isolates, but not in all patients' cells. These results show that, in addition to the direct targeting of Bcr-Abl, selective inhibition of Grb2 protein complexes may be a therapeutic option for a significant number of CML patients.

A simple stratification factor prognostic for survival in advanced cancer: the good/bad/uncertain index.

PURPOSE: This article summarizes the third step of a research program to identify variables that supplement the predictive power of the the Eastern Cooperative Oncology Group (ECOG) performance status (PS) for survival. The objective was to produce a simple, practical, stratification factor for phase III oncology clinical trials involving patients with advanced malignant disease. PATIENTS AND METHODS: A questionnaire was administered to 729 patients with metastatic colorectal or lung cancers. Patients provided a Karnofsky index and appetite rating while physicians provided a survival estimate and the ECOG-PS. Scores for each item were categorized as having a positive, neutral, or negative indication for survival. A patient was classified as having a relatively good prognosis if three or more of the four items showed a positive indication, a bad prognosis if three or more items were negative, and an uncertain prognosis otherwise (Good/Bad/Uncertain [GBU] index). RESULTS: The GBU index improved on the prognostic power of a Cox model quartile index and PS alone and increased the accuracy of survival classification estimates by 5% to 10% more than ECOG-PS alone. For patients with PS of 0 or 1, significant survival patterns exist between GBU groups (P=.002 and.0001, respectively). CONCLUSION: The GBU index may be recommended as a supplementary stratification factor for certain future phase III trials in metastatic lung or colorectal cancer where patient heterogeneity is a particular concern. The GBU represents a relatively modest increase to the cost and patient burden of a clinical trial given the additional control that is achieved over the potentially confounding concomitant to the treatment variable.

The C-terminal SH3 domain of the adapter protein Grb2 binds with high affinity to sequences in Gab1 and SLP-76 which lack the SH3-typical P-x-x-P core motif.

The adapter Grb2 is an important mediator of normal cell proliferation and oncogenic signal transduction events. It consists of a central SH2 domain flanked by two SH3 domains. While the binding specificities of the Grb2 SH2 and N-terminal SH3 domain [Grb2 SH3(N)] have been studied in detail, binding properties of the Grb2 SH3(C) domain remained poorly defined. Gab1, a receptor tyrosine kinase substrate which associates with Grb2 and the c-Met receptor, was previously shown to bind Grb2 via a region which lacks a Grb2 SH3(N)-typical motif (P-x-x-P-x-R). Precipitation experiments with the domains of Grb2 show now that Gab1 can bind stably to the Grb2 SH3(C) domain. For further analyses, Gab1 mutants were generated by PCR to test in vivo residues thought to be crucial for Grb2 SH3(C) binding. The Grb2 SH3(C) binding region of Gab1 has significant homology to a region of the adapter protein SLP-76. Peptides corresponding to epitopes SLP-76, Gab1, SoS and other proteins with related sequences, as well as mutant peptides were synthesized and analysed by tryptophan-fluorescence spectrometry and by in vitro competition experiments. These experiments define a 13 amino acid sequence with the unusual consensus motif P-x-x-x-R-x-x-K-P as required for a stable binding to the SH3(C) domain of Grb2. Additional analyses point to a distinct binding specificity of the Grb2-homologous adapter protein Mona (Gads), indicating that the proteins of the Grb2 adapter family may have partially overlapping, yet distinct protein binding properties.

Tamoxifen and chemotherapy for axillary node-negative, estrogen receptor-negative breast cancer: findings from National Surgical Adjuvant Breast and Bowel Project B-23.

PURPOSE: Uncertainty about the relative worth of doxorubicin/cyclophosphamide (AC) and cyclophosphamide/methotrexate/fluorouracil (CMF), as well as doubt about the propriety of giving tamoxifen (TAM) with chemotherapy to patients with estrogen receptor-negative tumors and negative axillary nodes, prompted the National Surgical Adjuvant Breast and Bowel Project to initiate the B-23 study. PATIENTS AND METHODS: Patients (n = 2,008) were randomly assigned to CMF plus placebo, CMF plus TAM, AC plus placebo, or AC plus TAM. Six cycles of CMF were given for 6 months; four cycles of AC were administered for 63 days. TAM was given daily for 5 years. Relapse-free survival (RFS), event-free survival (EFS), and survival (S) were determined by using life-table estimates. Tests for heterogeneity of outcome used log-rank statistics and Cox proportional hazards models to detect differences across all groups and according to chemotherapy and hormonal therapy status. RESULTS: No significant difference in RFS, EFS, or S was observed among the four groups through 5 years (P =.96,.8, and.8, respectively), for those aged < or = 49 years (P =.97,.5, and.9, respectively), or for those aged > or = 50 years (P =.7,.6, and.6, respectively). A comparison between all CMF- and all AC-treated patients demonstrated no significant differences in RFS (87% at 5 years in both groups, P =.9), EFS (83% and 82%, P =.6), or S (89% and 90%, P =.4). There were no significant differences in RFS, EFS, or S between CMF and AC in patients aged < or = 49 or > or = 50 years. No significant difference in any outcome was observed when chemotherapy-treated patients who received placebo were compared with those given TAM. RFS in both groups was 87% (P =.6), 87% in patients aged < or = 49 (P =.9), and 88% and 87%, respectively (P =.4), in those aged > or = 50 years. CONCLUSION: There was no significant difference in the outcome of patients who received AC or CMF. TAM with either regimen resulted in no significant advantage over that achieved from chemotherapy alone.

Cell-penetrating SH3 domain blocker peptides inhibit proliferation of primary blast cells from CML patients.

Bcr-Abl contributes prominently to the development of most chronic myeloid leukemias (CMLs). Prior work has identified the adapter protein CRKL as a major substrate of the Bcr-Abl tyrosine kinase. CRKL can also bind via its first SH3 domain [SH3(1)] to specific sequences in Bcr-Abl. Cell-penetrating peptides were developed that bind with high affinity and selectivity to the SH3(1) domain of CRKL. They disrupt Bcr-Abl-CRKL complexes and strongly reduce the proliferation of primary CML blast cells and cell lines established from Bcr-Abl-positive patients. Activation-specific antibodies against phosphorylated MAP kinase (MAPK) showed that MAPK activity is down-regulated in blast cells treated with the CRKLSH3(1) blocker peptides. We conclude that the Bcr-Abl-CRKL complexes are largely dependent on the CRKLSH3(1) domain, that the central mitogenic cascade is down-regulated as a consequence of the disruption of CRKLSH3(1) interactions, and that CRKL therefore contributes to the proliferation of CML blast cells.

The leukaemic oncoproteins Bcr-Abl and Tel-Abl (ETV6/Abl) have altered substrate preferences and activate similar intracellular signalling pathways.

Inappropriate activation of Abl family kinases plays a crucial role in different human leukaemias. In addition to the well known oncoproteins p190Bcr-Abl and p210Bcr-Abl, Tel-Abl, a novel fusion protein resulting from a different chromosomal translocation, has recently been described. In this study, the kinase specificities of the Bcr-Abl and Tel-Abl proteins were compared to the physiological Abl family kinases c-Abl and Arg (abl related gene). Using short peptides which correspond to the target epitopes in known substrate proteins of Abl family kinases, we found a higher catalytic promiscuity of Bcr-Abl and Tel-Abl. Similar to Bcr-Abl, Tel-Abl was found in complexes with the adapter protein CRKL. In addition, c-Crk II and CRKL are tyrosine phosphorylated and complexed with numerous other tyrosine phosphorylated proteins in Tel-Abl expressing Ba/F3 cells. GTPase analysis with a Ras-GTP-specific precipitation assay showed constitutive elevation of GTP-loaded Ras in cells expressing the leukaemic Abl proteins. The mitogenic MAPK/Erk kinases as well as Akt/PKB, a kinase implicated to negatively regulate apoptosis, were also constitutively activated by both Bcr-Abl and Tel-Abl. The results indicate that the leukaemic Abl-fusion proteins have catalytic specificities different from the normal kinases c-Abl and Arg and that Tel-Abl is capable to activate at least some pathways which are also upregulated by Bcr-Abl.

A phase II study of paclitaxel plus carboplatin as first-line chemotherapy for women with metastatic breast carcinoma.

BACKGROUND: This Phase II multicenter study evaluated the efficacy and toxicity of paclitaxel (200 mg/m(2) by 3-hour infusion) with carboplatin (area under the curve 6 mg/mL per minute) administered every 3 weeks as first-line therapy for women with metastatic breast carcinoma. METHODS: Eligible patients had measurable metastatic disease and an Eastern Cooperative Oncology Group performance status of 0-2. Prior adjuvant chemotherapy, including anthracycline-based therapy, was allowed, as was prior hormonal therapy as part of either adjuvant treatment or treatment for metastasis. Prior therapy with taxanes or platinum was not allowed. RESULTS: A total of 53 patients were enrolled in this study, with 50 patients evaluable for response and toxicity. The overall response rate was 62% (95% confidence interval ¿CI, 48-75%); 16% of patients had complete responses and 46% had partial responses. The median time to progression was 7.3 months (95% CI, 5.9-12.9), and the 12-month survival estimate was 72% (95% CI, 61-86%). Therapy was generally well tolerated. Grade 3-4 neutropenia was the predominant toxicity, observed in 82% of patients, but there were no episodes of febrile neutropenia or sepsis. Hematopoietic growth factors were not routinely necessary. Grade 3 peripheral neuropathy occurred in 16% of patients. CONCLUSIONS: Paclitaxel (200 mg/m(2)) with carboplatin (area under the curve 6 mg/mL per minute) demonstrated substantial efficacy in patients with metastatic breast carcinoma, and the 12-month survival rate of 72% was encouraging. This therapy represents a viable option for patients with metastatic disease.

Can breast cancer be prevented?

Breast cancer is the most common invasive cancer in American women and is second only to carcinoma of the lung in cancer deaths. The results of the National Surgical Adjuvant Breast and Bowel Project Breast Cancer Prevention Trial (BCPT) were released in April 1998. In the BCPT, 13,388 women at increased risk for the development of breast cancer were randomized to receive tamoxifen or placebo for 5 years, resulting in a 49% reduction in invasive breast cancer and a 50% reduction in noninvasive breast cancer. In May 1998, the preliminary results from the Multiple Outcomes of Raloxifene Evaluation (MORE) trial were reported to the American Society of Clinical Oncology. The MORE trial was evaluating the drug raloxifene for the prevention and treatment of osteoporosis; however, a secondary outcome was a reduction in breast cancer risk in raloxifene-treated women. Based upon the results of the BCPT and MORE trials, a second-generation breast cancer prevention trial has been initiated. The Study of Tamoxifen and Raloxifene (STAR) was initiated in June 1999. Ochsner Clinic and Alton Ochsner Medical Foundation, active participants in the BCPT, were named a clinical center for the STAR trial.

Further evaluation of intensified and increased total dose of cyclophosphamide for the treatment of primary breast cancer: findings from National Surgical Adjuvant Breast and Bowel Project B-25.

PURPOSE: In 1989, the National Surgical Adjuvant Breast and Bowel Project initiated the B-22 trial to determine whether intensifying or intensifying and increasing the total dose of cyclophosphamide in a doxorubicin-cyclophosphamide combination would benefit women with primary breast cancer and positive axillary nodes. B-25 was initiated to determine whether further intensifying and increasing the cyclophosphamide dose would yield more favorable results. PATIENTS AND METHODS: Patients (n = 2,548) were randomly assigned to three groups. The dose and intensity of doxorubicin were similar in all groups. Group 1 received four courses, ie, double the dose and intensity of cyclophosphamide given in the B-22 standard therapy group; group 2 received the same dose of cyclophosphamide as in group 1, administered in two courses (intensified); group 3 received double the dose of cyclophosphamide (intensified and increased) given in group 1. All patients received recombinant human granulocyte colony-stimulating factor. Life-table estimates were used to determine disease-free survival (DFS) and overall survival. RESULTS: No significant difference was observed in DFS (P =.20), distant DFS (P =.31), or survival (P =.76) among the three groups. At 5 years, the DFS in groups 1 and 2 (61% v 64%, respectively; P =. 29) was similar to but slightly lower than that in group 3 (61% v 66%, respectively; P = 08). Survival in group 1 was concordant with that in groups 2 (78% v 77%, respectively; P =.71) and 3 (78% v 79%, respectively; P =.86). Grade 4 toxicity was 20%, 34%, and 49% in groups 1, 2, and 3, respectively. Severe infection and septic episodes increased in group 3. The decrease in the amount and intensity of cyclophosphamide and delays in therapy were greatest in courses 3 and 4 in group 3. The incidence of acute myeloid leukemia increased in all groups. CONCLUSION: Because intensifying and increasing cyclophosphamide two or four times that given in standard clinical practice did not substantively improve outcome, such therapy should be reserved for the clinical trial setting.

Tamoxifen in treatment of intraductal breast cancer: National Surgical Adjuvant Breast and Bowel Project B-24 randomised controlled trial.

BACKGROUND: We have shown previously that lumpectomy with radiation therapy was more effective than lumpectomy alone for the treatment of ductal carcinoma in situ (DCIS). We did a double-blind randomised controlled trial to find out whether lumpectomy, radiation therapy, and tamoxifen was of more benefit than lumpectomy and radiation therapy alone for DCIS. METHODS: 1804 women with DCIS, including those whose resected sample margins were involved with tumour, were randomly assigned lumpectomy, radiation therapy (50 Gy), and placebo (n=902), or lumpectomy, radiation therapy, and tamoxifen (20 mg daily for 5 years, n=902). Median follow-up was 74 months (range 57-93). We compared annual event rates and cumulative probability of invasive or non-invasive ipsilateral and contralateral tumours over 5 years. FINDINGS: Women in the tamoxifen group had fewer breast-cancer events at 5 years than did those on placebo (8.2 vs 13.4%, p=0.0009). The cumulative incidence of all invasive breast-cancer events in the tamoxifen group was 4.1% at 5 years: 2.1% in the ipsilateral breast, 1.8% in the contralateral breast, and 0.2% at regional or distant sites. The risk of ipsilateral-breast cancer was lower in the tamoxifen group even when sample margins contained tumour and when DCIS was associated with comedonecrosis. INTERPRETATION: The combination of lumpectomy, radiation therapy, and tamoxifen was effective in the prevention of invasive cancer.

The Louisiana Cancer and Lung Trust Fund Board.

The Louisiana Cancer and Lung Trust Fund Board, begun in 1980, continues to move forward in its mission in cancer research and tobacco control. During the last year, the board has created a presence on the World Wide Web and taken steps to implement the Cancer Control Strategic Plan. It is also taking a lead role in the development of the Tobacco Control Coalition. Listed at the end of this article is a summary of the board's legislative mandate, its mission, and its current membership.

Prevention of breast cancer in high-risk women.

The results of the National Surgical Adjuvant Breast and Bowel Project (NSABP) Breast Cancer Prevention Trial (BCPT) were released in April 1998. In that trial, 13,388 women who were at high risk of developing breast cancer were randomized to receive tamoxifen or placebo for 5 years. There was a 49% (P < .00001) reduction in invasive breast cancer and a 50% (P < .002) reduction in noninvasive breast cancer. This is a major breakthrough in cancer prevention. The results of the BCPT are the basis for a second-generation prevention study; the STAR trial (Study of Tamoxifen and Raloxifene). Both the Ochsner Community Clinical Oncology Program (CCOP) and the Louisiana State University Minority-Based CCOP applied to participate in the STAR trial. Both applications were peer reviewed and both were approved. The STAR trial is being initiated in early 1999.

Herpesvirus ateles gene product Tio interacts with nonreceptor protein tyrosine kinases.

Herpesvirus ateles is a gamma-2-herpesvirus which naturally infects spider monkeys (Ateles spp.) and causes malignant lymphoproliferative disorders in various other New World primates. The genomic sequence of herpesvirus ateles strain 73 revealed a close relationship to herpesvirus saimiri, with a high degree of variability within the left terminus of the coding region. A spliced mRNA transcribed from this region was detected in New World monkey T-cell lines transformed by herpesvirus ateles in vitro or derived from T cells of infected Saguinus oedipus. The encoded viral protein, termed Tio, shows restricted homology to the oncoprotein StpC and to the tyrosine kinase-interacting protein Tip, two gene products responsible for the T-cell-transforming and oncogenic phenotype of herpesvirus saimiri group C strains. Tio was detectable in lysates of the transformed T lymphocytes. Dimer formation was observed after expression of recombinant Tio. After cotransfection, Tio was phosphorylated in vivo by the protein tyrosine kinases Lck and Src and less efficiently by Fyn. Stable complexes of these Src family kinases with the viral protein were detected in lysates of the transfected cells. Binding analyses indicated a direct interaction of Tio with the SH3 domains of Lyn, Hck, Lck, Src, Fyn, and Yes. In addition, tyrosine-phosphorylated Tio bound to the SH2 domains of Lck, Src, or Fyn. Thus, herpesvirus ateles-encoded Tio may contribute to viral T-cell transformation by influencing the function of Src family kinases.

A randomized trial of tamoxifen alone or combined with octreotide in the treatment of women with metastatic breast carcinoma.

BACKGROUND: Tamoxifen (TAM) is generally considered the hormonal agent of choice for postmenopausal women with hormone receptor positive breast carcinoma. The somatostatin analogues, including octreotide, have demonstrated inhibition of breast carcinoma cell lines and multiple endocrinologic actions, including reduction of insulin-like growth factor I (IGF-I), a potent mitogen for breast carcinoma cells. In an attempt to improve the efficacy of TAM, this randomized trial was performed. METHODS: One hundred thirty-five eligible postmenopausal women with metastatic breast carcinoma were randomized to TAM (10 mg twice daily) alone or combined with octreotide 150 microg (administered subcutaneously thrice daily). The two groups were well balanced, except the TAM group had higher proportions of patients with visceral disease (50% vs. 37%) and a disease free interval longer than 5 years (47% vs. 34%). A cohort of 18 patients was evaluated for the impact of treatment on serum IGF-I, free IGF-I, IGF binding protein 3 levels, and total IGF binding capacity. RESULTS: The median time to progression was estimated to be 14.2 months with TAM and 10.3 months with TAM plus octreotide. The distribution of progression free survival times revealed no significant difference (P = 0.26), and the progression hazard ratio (TAM/TAM + octreotide) was 0.81 (95% confidence interval [CI], 0.56-1.17). The distribution of survival times revealed no significant difference (P = 0.92), and the death hazard ratio was 0.98 (95% CI, 0.62-1.55). When the 106 patients with measurable or evaluable disease were considered, the objective response rate was 49% with TAM alone and 43% with TAM plus octreotide (P = 0.70). Patients who received TAM plus octreotide had higher incidences of nausea, diarrhea, and steatorrhea. The percentage of decline in serum IGF-I, from pretreatment levels to those following 3-6 weeks of treatment, was significantly greater (P < 0.01) with TAM plus octreotide than with TAM alone. CONCLUSIONS: There is no indication that the combination of TAM plus octreotide as administered in this study is substantially more efficacious than TAM alone in the treatment of postmenopausal women with metastatic breast carcinoma. The limited cohort included in IGF-I studies suggests that TAM plus octreotide produces a significantly greater reduction in serum IGF-I levels.