Stability of estrogen receptors in frozen human breast tumor tissue.
Author(s): Namkung PC, Moe RE, Petra PH
Publication: Cancer Res, 1979, Vol. 39, Page 1124-5
PubMed ID: 427754 PubMed Review Paper? No
Purpose of Paper
This paper assessed the effects of storing breast tumor specimens at -70°C for 3 days versus 1 month on cytosolic protein concentration and the concentrations of size-fractionated estrogen receptor proteins (fractions containing 4S and 8S ER were quantified separately) bound to radiolabeled estradiol.
Conclusion of Paper
When ER protein concentration was quantified using radiolabeled estradiol and the sucrose density gradient assay, breast tumor tissue specimens that were stored for 1 month at -70°C displayed an approximate 80% reduction in quantifiable 8S ER compared to case-matched specimens that were stored at the same temperature for 3 days (5-6 versus 21-28 fmol/mg, respectively), resulting in just 18-29% of 8S ER remaining after 1 month of storage. The concentration of 4S ER bound to radiolabeled estradiol was also affected by storage at -70°C for 1 month versus 3 days but to a less severe degree (4-10 versus 13-18 fmol/mg), with 22-77% of 4S ER remaining after 1 month of -70°C storage. The authors attribute the declines in the concentrations of 8S and 4S ER bound to radiolabeled estradiol to a loss of specific binding given that specimens stored for 3 days and 1 month did not differ in cytosolic protein concentration (6.43-8.11 versus 7.39-7.76 mg/ml, respectively). The authors also ruled out potential interference by steroid binding protein (which occurs in overlapping fractions with 4S ER) by all but abolishing binding with radioactive estradiol after incubation with the competitive ER ligand nafoxidine (which binds to 4S ER but not SBP).
Studies
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Study Purpose
This paper assessed the effects of storing breast tumor specimens at -70°C for 3 days versus 1 month on cytosolic protein concentration and the concentrations of size-fractionated estrogen receptor proteins (fractions containing 4S and 8S ER were quantified separately) bound to radiolabeled estradiol. Surgically resected breast tumor tissue from three patients was divided, frozen immediately (method not specified), and stored at -70°C for 3 days or 1 month. Fat was trimmed away, and 500 mg of frozen breast tumor was minced, homogenized with a polytron homogenizer, and centrifuged at 105,000 × g for 90 min at 0°C. Aliquots of the supernatant were incubated in 17 β-[3H]estradiol with and without the radioinert ER ligand nafoxidine. ER binding was determined by sucrose density gradient and cytosol protein was quantified by the Lowry assay.
Summary of Findings:
When bound ER protein was quantified using radiolabeled estradiol and the sucrose density gradient assay, breast tumor tissue specimens that were stored for 1 month at -70°C displayed an approximate 80% reduction in 8S ER compared to case-matched specimens that were stored at the same temperature for 3 days (5-6 versus 21-28 fmol/mg, respectively), resulting in just 18-29% of 8S ER remaining after 1 month of storage. The concentration of 4S ER bound to radiolabeled estradiol was also affected by storage at -70°C for 1 month versus 3 days but to a less severe degree (4-10 versus 13-18 fmol/mg), with 22-77% of 4S ER remaining after 1 month of -70°C storage. The authors attribute the declines in the concentrations of 8S and 4S ER bound to radiolabeled estradiol to a loss of specific binding given that specimens stored for 3 days and 1 month did not differ in cytosolic protein concentration (6.43-8.11 versus 7.39-7.76 mg/ml, respectively). The authors also ruled out potential interference by steroid binding protein (which occurs in overlapping fractions with 4S ER) by all but abolishing binding with radioactive estradiol after incubation with the competitive ER ligand nafoxidine (which binds to 4S ER but not SBP).
Biospecimens
Preservative Types
- Frozen
Diagnoses:
- Neoplastic - Carcinoma
Platform:
Analyte Technology Platform Protein Receptor binding Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Storage Storage duration 3 days
1 month