AAV2/8-humanFOXP3 gene therapy shows robust anti-atherosclerosis efficacy in LDLR-KO mice on high cholesterol diet

Inflammation is a key etiologic component in atherogenesis. Previously we demonstrated that adeno-associated virus (AAV) 2/8 gene delivery of Netrin1 inhibited atherosclerosis in the low density lipoprotein receptor knockout mice on high-cholesterol diet (LDLR-KO/HCD). One important finding from this study was that FOXP3 was strongly up-regulated in these Netrin1-treated animals, as FOXP3 is an anti-inflammatory gene, being the master transcription factor of regulatory T cells. These results suggested that the FOXP3 gene might potentially be used, itself, as an agent to limit atherosclerosis. To test this hypothesis AAV2/8 (AAV)/hFOXP3 or AAV/Neo (control) gene therapy virus were tail vein injected into the LDLR-KO/HCD animal model. It was found that hFOXP3 gene delivery was associated with significantly lower HCD-induced atherogenesis, as measured by larger aortic lumen cross sectional area, thinner aortic wall thickness, and lower aortic systolic blood velocity compared with Neo gene-HCD-treated controls. Moreover these measurements taken from the hFOXP3/HCD-treated animals very closely matched those measurements taken from the normal diet (ND) control animals. These data strongly suggest that AAV/hFOXP3 delivery gave a robust anti-atherosclerosis therapeutic effect and further suggest that FOXP3 be examined more stringently as a therapeutic gene for clinical use.

Sperm protein 17 is an oncofetal antigen: a lesson from a murine model

Sperm protein 17 (Sp17) was originally identified in the flagellum of spermatozoa and subsequently included in the subfamily of tumor-associated antigens known as cancer-testes antigens (CTA). Sp17 has been associated with the motility and migratory capacity in tumor cells, representing a link between gene expression patterns in germinal and tumor cells of different histological origins. Here we review the relevance of Sp17 expression in the mouse embryo and cancerous tissues, and present additional data demonstrating Sp17 complex expression pattern in this murine model. The expression of Sp17 in embryonic as well as adult neoplastic cells, but not normal tissues, suggests this protein should be considered an "oncofetal antigen." Further investigations are necessary to elucidate the mechanisms and functional significance of Sp17 aberrant expression in human adult cells and its implication in the pathobiology of cancer.

Final results of a phase I study using oral temozolomide (TMZ) daily for 14 days with weekly paclitaxel in patients (pts) with advanced malignancies

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Background: TMZ is an alkylating agent with activity in a variety of neoplasms. The optimal schedule of administration for TMZ has not been established and only a few studies have studied it in combination with other agents. Repair of TMZ-induced DNA damage is associated with the activity of O-6 alkylguanine-DNA-alkyl transferase (AGT). Preclinical and clinical data indicate that prolonged exposure to TMZ results, not only in enhanced DNA alkylation, but also in depletion of AGT. This serves as the rationale to study TMZ using protracted schedules. Methods: The aim of this study was to determine the maximum tolerated dose (MTD) and dose limiting toxicity (DLT) of oral TMZ given daily for 14 days with weekly paclitaxel in pts with advanced cancers. Forty-five pts received 136 cycles of TMZ at escalating doses (50, 75, 100, 125 and 150 mg/m2/day × 14 days) plus paclitaxel at 80 mg/m2 on days 1, 8, and 15. Pts were stratified as lightly (LP) or heavily (HP) pretreated and MTD defined as the dose level (DL) at which 1/6 patients developed DLT. Results: Twenty-four LP patients were treated at 5 DLs with all but one evaluable for toxicity. Febrile neutropenia and grade 3 thrombocytopenia were the DLTs. MTD in this group was the 125 mg/m2/day level. Twenty-six HP were treated at 5 DLs and 21 were evaluable for toxicity. Febrile neutropenia and grade 3 thrombocytopenia were the DLTs. MTD for this group was also 125 mg/m2/day. Thirty-eight (84%) pts were evaluable for response after 2 cycles of therapy. Three (8%) pts had a partial response (lung, lymphoma, ependymoma), 20 (53%) remained stable and 15 (39%) developed disease progression. Six (16%) pts remained stable for 6 cycles or more (2 sarcomas, 2 lung, 1 pancreas, 1 glioblastoma). Conclusions: We concluded that combining oral TMZ at a dose of 125 mg/m2/day for 14 days with standard-dose weekly paclitaxel is safe in both HP and LP pts.

[Table: see text]

[Rapid spontaneous resolution of acute subdural hematoma]

Acute subdural hematomas are usually neurosurgical emergencies, although a conservative therapy is indicated in selected cases. In some of these patients a progressive resolution is appreciated. However, rapid spontaneous resolution of an acute suddural hematoma is seldom reported. A patient with antecedent of chronic alcoholism and spontaneous resolution of acute subdural hematoma in less than 18 hours after the head injury is described. The possible mechanisms of this rapid resolution are discussed. A tear in the arachnoid with spilling of CSF into the subdural space and the effect of intracranial antihypertensive measures together with cerebral atrophy, are factors that possibly contribute to dilution and redistribution of blood with hematoma disappearing in CT scan.

Gene expression of insulin-like growth factors and receptors in neoplastic prostate tissues: correlation with clinico-pathological parameters

The insulin-like growth factor (IGF) system has been shown to regulate prostate cancer cell growth in vitro and, possibly, in vivo. In this study we examined RNA expression of IGF ligands and their receptors in 23 paired benign and neoplastic prostate tissues. In addition to comparing gene expression of IGF ligands and receptors between benign and neoplastic tissue samples, we correlated IGF-I, IGF-II, IGFR-1, and IGFR-2 RNA levels in tumor samples with prognostic clinico-pathological parameters such as stage, grade, Gleason score, perineural or extraprostatic invasion. We found higher IGF-I RNA levels in benign vs. malignant tissues (p = 0.014), whereas IGF-II RNA expression was higher in tumors with high Gleason score (GS) (p = 0.045). Using the Spearman rank correlation test we also found a positive correlation between IGFR-2 RNA levels and GS (p = 0.01). No correlation was found between expression of IGF ligands and receptors and tumor grade, stage perineural invasion, or extraprostatic involvement. We conclude that differential expression of certain IGF system components may be important in the biology and clinical behavior of prostate cancer.

Effect of hemodialysis on topotecan disposition in a patient with severe renal dysfunction

The pharmacokinetics of topotecan have been extensively studied in patients with normal renal function and there is one study of patients with mild to moderate renal insufficiency. However, the effect of hemodialysis on topotecan disposition has not been reported. The objective of this study was to characterize the disposition of topotecan in a patient with severe renal insufficiency receiving hemodialysis. Topotecan lactone disposition was characterized in a patient on and off hemodialysis. The topotecan lactone clearance determined after administration of topotecan alone and with hemodialysis was 5.3 l/h per m(2) vs 20.1 l/h per m2 respectively. At 30 min after the completion of hemodialysis, the topotecan plasma concentration obtained was greater than that measured at the end of hemodialysis (i.e. 8.0 ng/ml vs 4.9 ng/ml), suggesting a rebound effect. The topotecan terminal half-life off dialysis was 13.6 h, compared with an apparent half-life determined during hemodialysis of 3.0 h. These results demonstrate that topotecan plasma clearance while on hemodialysis increased approximately fourfold. Hemodialysis may be an effective systemic clearance process for topotecan and should be considered in selected clinical situations (e.g. inadvertent overdose, severe renal dysfunction).

Differential expression of insulin-like growth factor binding proteins in high versus low Gleason score prostate cancer

PURPOSE

The insulin-like growth factor (IGF) system appears to be important in human prostate cancer biology. Expression of specific IGF binding proteins (IGFBPs) by prostate cancer tissues may modulate IGF cellular actions, and possibly determine both IGF-dependent tumor growth and biological aggressiveness in vivo. The purpose of this study was to examine the differential expression of all six IGFBP genes in benign and malignant prostate tissue samples.

MATERIALS AND METHODS

Using RNAse protection assays, we examined expression of IGFBPs 1 through 6 in 23 paired benign and neoplastic prostate tissue samples obtained from the same prostatectomy specimen. RNA expression levels on each tissue sample were determined densitometrically and groups compared using standard Student's t test.

RESULTS

We found expression of IGFBPs 2 through 6, but not IGFBP-1, in both malignant and benign tissues. A statistically significant differential expression of IGFBPs 2, 3 and 5 was found between tumors with high Gleason score and those with low scores and benign tissues. Expression of IGFBPs 2 and 5 was higher (p = 0.002 and 0.04, respectively) while that of IGFBP-3 was lower (p = 0.05) in high versus low Gleason score cancer specimens. Expression of IGFBPs 4 and 6 was no different between tumors (p = 0.052 and 0.25, respectively). No significant differences in IGFBP expression were evident between benign and tumor tissues when tumor grade was not considered.

CONCLUSION

Our results indicate that differential expression of certain IGFBPs in human prostate cancer correlates with tumor Gleason score. Thus, expression of certain IGFBPs in prostate cancer may be used as a surrogate marker of aggressive clinical behavior.

Corticosteroids alter hematopoiesis in vitro by enhancing human monocyte secretion of granulocyte colony-stimulating factor

The mechanism of corticosteroid alteration of hematopoiesis is not completely elucidated. Employing an endotoxin free system, we examined the mechanisms by which hydrocortisone succinate (HCS) enhanced human bone marrow (BM) colony forming unit granulocyte-macrophage (CFU-GM) proliferation. Interleukin-1beta (IL-1) (1 ng/mL), granulocyte-macrophage colony-stimulating factor (GM-CSF) (1 ng/mL), or the combination, induced minimal CFU-GM proliferation unless HCS was added to the cultures (10-25 vs. 80-125 colonies/4x10(5) BM mononuclear cells). Supernatants produced by incubating mononuclear cells with IL-1 + GM-CSF +/- HCS were examined for their capacity to induce CFU-GM proliferation: IL-1 and/or GM-CSF failed to induce supernatants capable of supporting CFU-GM proliferation unless HCS was present. Analysis of the cytokines produced by mononuclear cell subpopulations demonstrated that HCS markedly enhanced IL-1-induced monocyte secretion of granulocyte (G)-CSF. Furthermore, the minimal effective concentration of IL-1 required to induce G-CSF release was reduced 10-fold (from 1 to 0.1 ng/mL) and the G-CSF released was increased 5-fold at an IL-1 concentration of 1 ng/mL. In contrast, IL-1-induced monocyte secretion of tumor necrosis factor (TNF) was inhibited by HCS. HCS enhanced G-CSF secretion at physiologic concentrations (10 microg/dL), whereas progesterone had no effect. HCS alone had no effect on G-CSF secretion or mRNA expression while IL-1+HCS resulted in a 3-fold increase in G-CSF mRNA levels. These data suggest for the first time that corticosteroids increase secretion of an essential component of the lymphohematopoietic cytokine-growth factor system.

Severe necrosis due to paclitaxel extravasation

Paclitaxel is an antineoplastic agent derived from the bark of the Pacific yew tree that has activity against many tumors including breast and ovarian carcinomas. In the past, its extravasation quality has been considered to be a local irritant; however, recent reports suggest that the agent may be a vesicant. A patient experienced a delayed vesicant reaction to a paclitaxel extravasation that resulted in severe necrosis. No acute symptoms were reported at the time of extravasation from the 24-hour peripheral paclitaxel infusion. However, on day 11 the patient complained of severe and progressive pain at the site of extravasation. The site was erythematous and had areas of central necrosis requiring debridement and closure by a plastic surgeon. Because paclitaxel possesses vesicant characteristics, health care professionals should be aware of its potential extravasation hazard. Prolonged peripheral infusions should be avoided or administered with extreme caution.

Correlation of insulin-like growth factor-binding protein-3 messenger RNA with protein expression in primary breast cancer tissues: detection of higher levels in tumors with poor prognostic features

BACKGROUND

The insulin-like growth factor (IGF)-binding proteins (IGFBPs) regulate the actions of the IGFs by influencing interactions between the IGFs and the IGF receptors. IGFBP-3, one of the six known species of IGFBPs, is the predominant IGFBP in serum and is expressed by breast cancer cells. Compared with estrogen receptor (ER)-positive samples, ER-negative breast cancer cell lines and tumors express higher levels of IGFBP-3. Therefore, expression of IGFBP-3 may be relevant in breast cancer biology, although it is unknown whether IGFBP-3 levels correlate with other breast cancer prognostic factors besides ER status. It is also not known how different methods used to measure IGFBP-3 in breast cancer correlate.

PURPOSE

We measured IGFBP-3 messenger RNA (mRNA) and protein levels in breast tumors by different methods to test how these methods compare and to investigate the relationship between IGFBP-3 and breast cancer prognostic factors.

METHODS

We analyzed 40 human breast tumors and examined IGFBP-3 expression by ligand blot analysis, immunoblot analysis, immunoradiometric assay (IRMA), and ribonuclease protection assay. Another set of 40 breast tumors, selected according to ER and progesterone receptor (PR) status, S phase, and ploidy, was analyzed by IRMA.

RESULTS

In 26 (65%) of 40 samples in which RNA could be isolated, IGFBP-3 mRNA levels correlated with IGFBP-3 levels measured by IRMA (two-sided; P = .0001) but not with IGFBP-3 levels measured by ligand blot or immunoblot. Protein levels were highly correlated among all protein assays. Because the IRMA was more sensitive and accurate than the ligand blot and immunoblot assays, we used IRMA to examine IGFBP-3 levels in an additional 20 primary breast tumors with poor prognostic features (ER and PR negativity, high S phase, and aneuploidy) and in 20 tumors with good prognostic factors (opposite features). IGFBP-3 levels were threefold higher in tumors with poor prognostic features (mean +/- standard deviation = 32.8 +/- 25.2 versus 11.8 +/- 9.7 ng/mg; two-sided; P = .003).

CONCLUSIONS

These findings suggest that in human breast cancer, IGFBP-3 mRNA and protein levels are correlated and higher levels of IGFBP-3 are detectable in tumors with poor prognostic features.

IMPLICATIONS

IGFBP-3 may be involved in the regulation of breast cancer cell growth.

Proliferation of cultured human prostate cancer cells is inhibited by insulin-like growth factor (IGF) binding protein-1: evidence for an IGF-II autocrine growth loop

In this study, we examined the expression of insulin-like growth factor (IGF) ligands, receptors, (IGFR1, IGFR2), and binding proteins (IGFBPs) in the human prostate cancer cell line DU145, as well as its mitogenic response to the IGFs. Using RNase protection assays, we found expression of IGF-II, IGFR1, and IGFR2 but failed to detect IGF-I messenger RNA. Distinct binding protein species as well as immunoreactive IGF-II were detected in conditioned media using radioligand and immunoblotting assays. Compared with controls, treatment with exogenous IGF-I and IGF-II resulted in stimulation of monolayer and anchorage-independent growth. Recombinant human IGFBP-1, which binds IGF-II with high affinity, inhibited IGF-II-induced monolayer growth and both baseline and IGF-II-induced anchorage-independent growth in this cell line. Our data suggest IGF-II is as an autocrine growth factor in DU145 cells, and that inhibition of IGF-II-dependent growth of human prostate cancer cells may represent a new therapeutic strategy for this disease.

Detection of insulin-like growth factor binding proteins (IGFBPs) by ligand blotting in breast cancer tissues

Eighty breast cancer specimens were examined for insulin-like growth factor binding protein (IGFBP) expression by ligand blotting. Five distinct IGFBP species were found: a doublet at 48 and 44 kDa was IGFBP-3, the 34-kDa band was IGFBP-2, and a band at 24 kDa was IGFBP-4. A 32-kDa band was compatible with the migration position reported for IGFBP-5. IGFBP-3 was inversely correlated with ER expression, while IGFBP-4 was positively correlated with both ER and PgR. IGFBP-4 was also inversely correlated with S-phase fraction. Thus, IGFBP expression correlates with other parameters of breast cancer biology and may play a role in regulating tumor growth.

Insulin-like growth factor binding protein 1 expression inhibits insulin-like growth factor I action in MCF-7 breast cancer cells

Interactions between insulin-like growth factor I (IGF-I) and the type of I IGF receptor may be affected by high-affinity extracellular binding proteins. To date, six distinct IGF binding proteins (IGFBPs) have been identified, but their physiological roles are not well understood. For example, depending on experimental conditions, IGFBP-1 has been shown to both enhance and inhibit IGF-I mediated mitogenesis. We have previously shown that excess exogenous IGFBP-1 inhibited IGF-I mediated growth of MCF-7 cells. In this study, we examined whether or not endogenously expressed IGFBP-1 could interfere with IGF-I mediated growth of MCF-7 cells. Cells were stably transfected with an IGFBP-1 expression vector. IGFBP-1 mRNA was produced by the cells, and protein was detected in the conditioned media by ligand blot and immunoblot. Type I IGF receptor could not be phosphorylated by IGF-I in cells expressing IGFBP-1; however, an IGF-I analogue (Arg-3-IGF-I), which cannot complex with IGFBPs, stimulated receptor phosphorylation. IGF-I did not stimulate cell growth in IGFBP-1 expressing cells. These results suggest that IGFBP-1 expression in MCF-7 breast cancer cells inhibits IGF-I induced growth by interrupting the interaction between IGF-I and its receptor.

Recombinant insulin-like growth factor binding protein-1 inhibits IGF-I, serum, and estrogen-dependent growth of MCF-7 human breast cancer cells

The insulin-like growth factors (IGFs) are potent mitogens for breast cancer cells and their activity is modulated by high affinity binding proteins (IGFBPs). We have recently shown that IGFBP-1 purified from human amniotic fluid neutralizes IGF-I-dependent growth of MCF-7 cells. In this study we examined the effects of recombinant IGFBP-1 (rBP-1) on IGF-I, estradiol (E2), and serum-induced monolayer and anchorage independent growth (AIG) of MCF-7 cells. Under serum-free conditions, rBP-1 had no effect on MCF-7 basal monolayer growth. However, 40 nM rBP-1 completely blocked the mitogenic action of both IGF-I and 5% charcoal stripped serum (CSS). This concentration of rBP-1 partially inhibited E2-induced growth, while 80 nM rBP-1 completely abolished E2 mitogenicity. The addition of either excess IGF-I or 5 nM [Arg3]IGF-I, a species that does not bind IGFBPs, neutralized rBP-1 inhibitory effects. In AIG assays, 80 nM rBP-1 reduced colony number by at least 70% and decreased colony size in all treatment groups compared to control. We examined rBP-1 effects on both IGF-I binding to MCF-7 membranes and activation of type I IGF receptor (IGFR1) and found that 80 nM rBP-1 reduced IGF-I receptor binding to levels of nonspecific binding and completely abolished ligand-dependent IGFR1 phosphorylation. However, neither treatment with 5% CSS nor exposure to E2 resulted in IGFR1 phosphorylation suggesting that different mechanism(s) are responsible for rBP-1 inhibitory action under this condition. Our data suggest rBP-1 may serve as an antagonist of human breast cancer growth by interfering with growth factor-mediated cell proliferation.

Expression of insulin-like growth factor binding proteins in human breast cancer correlates with estrogen receptor status

The insulin-like growth factors (IGFs) have been implicated in the growth regulation of human breast cancer. Since the IGFs are associated with specific binding proteins (IGFBPs) which may modulate receptor/ligand interactions, production of IGFBPs by breast cancer cells could alter their IGF-dependent growth. This study examined the expression of IGFBPs 4, 5, and 6 in eight breast cancer cell lines (BCCLs) using ribonuclease (RNase) protection assays. IGFBP-4 mRNA was detected in all BCCLs studied. IGFBP-5 expression was higher in estrogen receptor (ER) positive cells, while IGFBP-6 mRNA was detected in only two ER negative BCCLs. We also found that E2 treatment enhanced the expression of IGFBPs 2, 4, and 5 in T47-D cells. We next studied IGFBP mRNA expression in 40 primary breast tumors. All tumors expressed mRNA for IGFBPs 2-6 but none expressed IGFBP-1 message. IGFBP-3 expression was higher in ER negative tumors, while that of IGFBP-4 and -5 was higher in ER positive specimens. These differences were statistically significant (P < .05). Ligand blot analysis of tumor extracts confirmed the presence of IGFBPs in breast cancer tissues. Thus, differential IGFBP expression in ER positive and negative tumors suggests an important role for this protein in breast cancer biology.

Prognostic indicators in early breast cancer

Approximately 115,000 new cases of axillary node negative breast cancer were diagnosed in this country last year. Since about 20-30% of these patients will ultimately relapse and die of their disease, adjuvant systemic therapy has been advocated for this group to decrease the relapse rate and prolong survival. However, although most clinical trials have demonstrated a modest impact on disease recurrence, the available data have failed to show consistent improvements in overall survival and does not justify the generalized use of systemic treatment in this patient subgroup. For this reason, a plethora of prognostic factors have been described to identify those patients with a higher risk of recurrence to concentrate therapeutic options in this specific group. Of all the disease prognosticators studied, tumor size, nuclear grade, and proliferative indexes appear to correlate well with tumor recurrence. In addition, biologic characteristics of primary tumors such as the presence of hormone and growth factor receptors, secretion of specific polypeptides and proteases, expression of proto-oncogenes, and abnormalities in tumor suppressor genes have been shown to be potentially useful as prognostic indicators in patients with early breast cancer. Despite these provocative data, larger clinical trials are necessary before incorporating these parameters in the routine evaluation of patients with axillary node negative breast cancer.

Regulation of insulin-like growth factor binding proteins in ovarian cancer cells by oestrogen

Insulin-like growth factor-I (IGF-I), its receptor and its binding proteins are expressed by ovarian cancer cells. In this study, we examined oestradiol (E2) regulation of IGF-I and IGF binding proteins (IGFBP) in an oestrogen-responsive ovarian cancer cell line, PE04. In serum-free conditions, PE04 cell monolayer growth was increased 1.64-fold by 3 nmol/l E2 compared with controls, although IGF-I mRNA levels were not increased. In contrast to IGF-I mRNA, IGFBP mRNA was regulated by E2. E2 caused a marked decrease in IGFBP-3 RNA, but IGFBP-2, -4 and -6 levels were only minimally depressed. IGFBP-5 mRNA levels were increased by E2. Tamoxifen had less effect on IGFBP mRNA regulation. Ligand blotting showed that E2 reduced IGFBP levels in conditioned media. IGFBP RNA was also detected in human ovarian tissue samples. Thus, IGFBP expression can be regulated in oestrogen-responsive ovarian cancer by E2.

Regulation of insulin-like growth factor-binding protein (IGFBP) expression by breast cancer cells: use of IGFBP-1 as an inhibitor of insulin-like growth factor action

BACKGROUND

The insulin-like growth factors (IGFs) play an important role in normal growth and development. Evidence suggests they may also regulate the growth of several cancer cell types. This regulation is mediated by interactions between the receptors and ligands. There is now ample evidence to suggest that these interactions are also influenced by extracellular IGF-binding proteins (IGFBPs). Six different IGFBPs have been cloned. Some species may act to inhibit the mitogenic effects of the IGFs. Since breast cancer cells are responsive to the IGFs, it is possible that regulated expression of the IGFBPs affects tumor growth. Furthermore, inhibitory binding proteins could be used as neutralizers of IGF action.

PURPOSE

We conducted this study to fully characterize the expression and hormonal regulation of IGF-binding protein expression in human MCF-7 breast cancer cells and to test the ability of purified IGFBP-1 to inhibit IGF-I action.

METHODS

We used ribonuclease protection assays and Western ligand blotting to examine IGFBP expression in MCF-7 cells. The effect of IGF-I, IGFBP-1, and 17 beta-estradiol on serum-free cell growth was also studied.

RESULTS

MCF-7 cells expressed IGFBP-2, IGFBP-4, and IGFBP-5 RNA and protein. These cells are dependent on estrogen for growth. In short-term culture, IGF-I can substitute for estrogen. Concomitant addition of IGF-I and estrogen enhanced stimulation above the level achieved by either factor alone. Estrogen also increased IGFBP production, making it unlikely that the IGFBPs induced by estrogen in MCF-7 cells could function as major inhibitors of IGF action. In contrast, exogenous addition of IGFBP-1 could block IGF-I-induced mitogenesis; this effect was reversible by excess IGF-I.

CONCLUSIONS

The studies suggest that cancer cell growth may be regulated by endogenous IGFBP expression. Furthermore, the exogenous addition of the IGFBP-1 blocked IGF-I action and potentially could be used as a pharmacologic inhibitor of IGF action.

The insulin-like growth factor binding proteins (IGFBPs) in human breast cancer

Several lines of evidence suggest that IGFs are important regulators of breast cancer cell growth. Unlike other growth factors, the IGFs interact with specific binding proteins in all extracellular fluids. To date, six different IGFBPs have been cloned, although their exact physiological function is not understood. Experimental evidence accumulated over the past few years suggests that IGFBPs could function as modulators of IGF actions in a variety of systems. This includes breast cancer, since several groups have demonstrated the production of IGFBPs by human breast cancer cells. We have found that the pattern of expression of these binding proteins is heterogeneous and varies depending on the breast cancer cell ER status. We have also shown that estrogen is capable of regulating the expression of certain IGFBPs in MCF-7 cells. Specifically, estradiol enhanced the expression of IGFBP 2, 4, and 5, and decreased that of IGFBP-3 in this cell line. Since the IGFBPs can modulate IGF actions in different experimental systems, we and others have studied their potential role as inhibitors of IGF-induced mitogenesis in breast cancer cells. We have demonstrated that purified IGFBP-1 neutralized IGF-dependent growth of MCF-7 cells in a reversible manner. These results suggest that the IGFBPs might be used to inhibit IGF-mediated breast cancer proliferation.

[Familial neoplasms and childhood dermatomyositis]

Familial frequency of malignant neoplasms from 20 children with dermatomyositis was investigated and compared with 225 controls. Eight patients with dermatomyositis (40 per cent) had nine family members with a malignant tumour; this frequency is significantly higher than those found in the controls with juvenile rheumatoid arthritis (P less than 0.01), neoplasms (P less than 0.01), and a variety of diseases (P less than 0.05). This finding and the known association of neoplasm-dermatomyositis might suggest an hereditary predisposing factor, possibly a subtle inmune deficiency, common for tumours and dermatomyositis.