IMPORTANCESeminal investigation 2 decades ago alerted the oncology community to age disparities in participation in cooperative group trials; less is known about whether these disparities persist in industry-funded research. OBJECTIVE To characterize the age disparities among trial enrollees on randomized clinical trials (RCTs) of common cancers in clinical oncology and identify factors associated with wider age imbalances. DATA SOURCES Phase 3 clinical oncology RCTs were identified through ClinicalTrials.gov. STUDY SELECTION Multiarm RCTs assessing a therapeutic intervention for patients with breast, prostate, colorectal, or lung cancer (the 4 most common cancer disease sites) were included. DATA EXTRACTION AND SYNTHESIS Trial data were extracted from ClinicalTrials.gov. Trial screening and parameter identification were independently performed by 2 individuals. Data were analyzed in 2018. MAIN OUTCOMES AND MEASURESThe difference in median age (DMA) between the trial participant median age and the population-based disease-site-specific median age was determined for each trial.RESULTS Three hundred two trials met inclusion criteria. The trials collectively enrolled 262 354 participants; 249 trials (82.5%) were industry-funded. For all trials, the trial median age of trial participants was a mean of 6.49 years younger than the population median age (95% CI, −7.17 to −5.81 years; P < .001). Age disparities were heightened among industry-funded trials compared with non-industry-funded trials (mean DMA, −6.84 vs −4.72 years; P = .002). Enrollment criteria restrictions based on performance status or age cutoffs were associated with age disparities; however, industry-funded trials were not more likely to use these enrollment restrictions than non-industry-funded trials. Age disparities were also larger among trials that evaluated a targeted systemic therapy and among lung cancer trials. Linear regression modeling revealed a widening gap between trial and population median ages over time at a rate of −0.19 years annually (95% CI, −0.37 to −0.01 years; P = .04). CONCLUSIONS AND RELEVANCEAge disparities between trial participants and the incident disease population are pervasive across trials and appear to be increasing over time. Industry sponsorship of trials is associated with heightened age imbalances among trial participants. With an increasing role of industry funding among cancer trials, efforts to understand and address age disparities are necessary to ensure generalizability of trial results as well as equity in trial access.

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SUMMARY A thermolabile protein with the properties of a steroid 'receptor' was identified in the cytoplasmic or 105,000 g supernatant fraction of the rat prostate. The receptor has a particular binding specificity towards 5αdihydrotestosterone. Testosterone is bound to a lesser extent but other steroids, including certain androgenic hormones, are not bound. The sedimentation coefficient of 8·0 s and the frictional ratio of 1·96, equivalent to a molecular weight of 2·74 × 105, clearly distinguish the soluble androgen-receptor from the androgen-binding globulin in serum and the androgen-receptor in the prostatic nucleus. Like the nuclear receptor, however, the soluble receptor is probably an acidic protein. Both cysteine and tryptophan residues appear necessary for maintaining the functional configuration of the receptor.

1. A system has been developed for the specific transfer of [(3)H]dihydrotestosterone-receptor complexes into prostatic chromatin in vitro. 2. Under optimum conditions the overall transfer of [(3)H]dihydrotestosterone into purified chromatin in this reconstituted system is entirely consistent with the results obtained in whole tissue both in vivo and in vitro. 3. The transfer of [(3)H]dihydrotestosterone into chromatin is tissue-specific and maximal into chromatin isolated from androgen-dependent tissues. 4. The tissue specificity is maintained at two levels: first, in the presence of specific cytoplasmic androgen-receptor proteins; secondly, by the nature and composition of the chromatin itself. 5. Evidence is presented that androgenic steroids in vivo may maintain the tissue-specific nature of chromatin in androgen-dependent tissues by the selective induction of nuclear protein synthesis. 6. The relevance of these findings to the mechanism of action of androgenic steroids is discussed.

1. Two basic proteins were purified from secretions of rat seminal vesicles by using Sephadex G-200 chromatography and polyacrylamide-gel electrophoresis under denaturing conditions. 2. It is not certain that these two proteins are distinct species and not subunits of a larger protein, but their properties are similar. Highly basic (pI = 9.7), they migrate to the cathode at high pH and their amino acid composition shows them to be rich in basic residues and serine. Threonine and hydrophobic residues are few. Both proteins are glycoproteins and have mol.wts. of 17000 and 18500. 3. Together these two proteins account for 25-30% of the protein synthesized by the vesicles, but they are absent from other tissues. 4. Changes in androgen status of the animal markedly affect these proteins. After castration, a progressive decrease in the basic proteins is observed and the synthesis of the two proteins as measured by [35S]methionine incorporation in vitro is is decreased. Testosterone administration in vivo rapidly restores their rates of synthesis. 5. These effects on specific protein synthesis are also observed for total cellular protein, and it is suggested that testosterone acts generally on the total protein-synthetic capacity of the cell and not specifically on individual proteins. Proliferative responses in the secretory epithelium may also be involved. 6. The extreme steroid specificity of the induction process suggests that the synthesis of these basic proteins is mediated by the androgen-receptor system. 7. The biological function of these proteins is not clear, but they do not appear to be involved in the formation of the copulatory plug.

The presence of three major proteins alpha, beta and gamma in rat ventral prostate was demonstrated by electrophoresis in polyacrylamide gels containing sodium dodecyl sulphate. Their regulation by androgens was studied by measuring the rates of synthesis of the proteins in minced prostatic tissue by using L-[35S]methionine. The three proteins account for 30-40% of the proteins synthesized in the gland. After castration, their rates of synthesis rapidly decline to about 1% that of normal animals, and this cannot be accounted for by the accompanying decrease in general protein synthesis. Testosterone reverses these changes in castrated animals, so that after 4 days normal synthesis is restored. The regulation is specific for androgens, since cyproterone acetate, an anti-androgen, is inhibitory and oestradiol-17beta and corticosterone are without effect. Preliminary characterization of the proteins indicates that protein alpha (mol.wt. 22000, pI unknown) is a glycoprotein containing glucose and/or mannose residues and occurs in both the mitochondrial and cytosol fractions. Protein beta (mol.wt. 12000, pI5.4) is also a glycoprotein, but is found exclusively in the cytosol fraction. Protein gamma (mol.wt. 8000, pI5.4) is also a glycoprotein, but is found exclusively in the cytosol fraction. Protein gamma (mol.wt. 8000, pI5.4) is also found exclusively in the cytosol fraction.

1. Two characteristic properties of the specific high-affinity steroid-binding proteins or receptors, their ability to bind to DNA-cellulose and their relatively acidic isoelectric point, have been exploited as a means of purification. These two fundamental properties distinguish the receptors from the steroid-binding proteins in serum and the non-specific low-affinity steroid-binding proteins in hormone-responsive cells. 2. A significant degree of purification of both cytoplasmic and nuclear steroid-receptor complexes can be achieved with practical facility by these procedures. The purity of the receptor complexes is sufficient to enable studies on their possible control of metabolic processes to be investigated in the future. 3. After extensive purification the physicochemical properties of the cytoplasmic androgen-receptor complex, such as sedimentation coefficient, were unchanged. Further, the purified complex fully retained at least one of its fundamental physiological properties, namely the ability to transfer 5alpha-dihydrotestosterone (17beta-hydroxy-5alpha-androstan-3-one) into chromatin in vitro. 4. The methods may also be employed for studying the changes in the structure and properties of the receptor complexes that are an essential prerequisite for the transfer of cytoplasmic receptor complexes into nuclear chromatin. The temperature-dependence of the binding of androgen-receptor complexes into chromatin is essentially due to a major change in cytoplasmic receptor complex before its attachment to nuclear chromatin. 5. The resolution of these analytical procedures was sufficient to enable a critical comparison of the receptor proteins from different male accessory glands to be undertaken. From these studies, no substantial evidence in support of the tissue specificity of androgen receptors could be established; rather the receptors from different androgen-dependent glands were remarkably similar in physicochemical properties. 6. Although the methods were initially developed for the partial purification of androgen-receptor complexes, they are equally suitable for the prompt and extensive purification of oestrogen-receptor and progesterone-receptor complexes.