BACKGROUND:The technique of ultrasound processing is widely used for molecular biological analysis.It is of great significance to study the DNA quality of tissue with different storage years under new ultrasonic treatment for further specimen quality control of molecular detection.OBJECTIVE:To explore the effects of different storage durations on DNA quality in specimens with ultrasound processing to investigate the optimal storage time for molecular tests.METHODS:Forty specimens of breast biopsy were collected and paraffin specimens were prepared by ultrasonography.These specimens were divided into four groups based on their storage periods:<1 year,1-3 years,>3-5 years,and>5 years,which contained 10 cases in each group.Paraffin specimens were sliced;each slice was 3 μm thick;10-15 slices were taken,and DNA was extracted.The mass concentration of DNA was examined by Nanophotometer N60 ultra-micro spectrophotometer and Qubit 4.0 fluorometer.The purity of the DNA was analyzed by the ratio of A260/A280.DNA fragment integrity was measured by capillary electrophoresis (Qsep 100) to evaluate the quality of the DNA fragments.RESULTS AND CONCLUSION:The mean values of A260/A280 in the four groups were between 1.8 and 2.0,meeting the requirements of tests,without significant differences.The mean values of DNA mass concentration (Qubit concentration) were 30.39,14.33,2.52,and 1.95 ng/μL,respectively.The mean values of the N/Q were 6.48,14.18,24.56,and 29.86.The mean values of DNA were:5.64,1.76,1.24,and 0.80.The percentage of large DNA fragments averaged 56.08％,17.72％,12.68％,and 7.90％.Moreover,the Ct values of the internal control detected by PCR were 15.32,17.09,18.39,and 21.24.The three other groups exhibited significantly lower DNA concentration,higher N/Q ratios,decreased DNA quality and percentage of large fragments,and increased values of Ct,compared with the group of within 1 year of storage (P<0.05).The experimental results suggested that for novel ultrasound processed biopsy specimens,we should prioritize samples stored within 1 year for molecular testing.Samples stored within 3 years can also meet the requirements of second-generation sequencing and other tests.Samples stored within 5 years can only be attempted to carry out PCR.Samples stored for more than 5 years were not recommended to carry out molecular tests.

BACKGROUND:The technique of ultrasound processing is widely used for molecular biological analysis.It is of great significance to study the DNA quality of tissue with different storage years under new ultrasonic treatment for further specimen quality control of molecular detection.OBJECTIVE:To explore the effects of different storage durations on DNA quality in specimens with ultrasound processing to investigate the optimal storage time for molecular tests.METHODS:Forty specimens of breast biopsy were collected and paraffin specimens were prepared by ultrasonography.These specimens were divided into four groups based on their storage periods:<1 year,1-3 years,>3-5 years,and>5 years,which contained 10 cases in each group.Paraffin specimens were sliced;each slice was 3 μm thick;10-15 slices were taken,and DNA was extracted.The mass concentration of DNA was examined by Nanophotometer N60 ultra-micro spectrophotometer and Qubit 4.0 fluorometer.The purity of the DNA was analyzed by the ratio of A260/A280.DNA fragment integrity was measured by capillary electrophoresis (Qsep 100) to evaluate the quality of the DNA fragments.RESULTS AND CONCLUSION:The mean values of A260/A280 in the four groups were between 1.8 and 2.0,meeting the requirements of tests,without significant differences.The mean values of DNA mass concentration (Qubit concentration) were 30.39,14.33,2.52,and 1.95 ng/μL,respectively.The mean values of the N/Q were 6.48,14.18,24.56,and 29.86.The mean values of DNA were:5.64,1.76,1.24,and 0.80.The percentage of large DNA fragments averaged 56.08％,17.72％,12.68％,and 7.90％.Moreover,the Ct values of the internal control detected by PCR were 15.32,17.09,18.39,and 21.24.The three other groups exhibited significantly lower DNA concentration,higher N/Q ratios,decreased DNA quality and percentage of large fragments,and increased values of Ct,compared with the group of within 1 year of storage (P<0.05).The experimental results suggested that for novel ultrasound processed biopsy specimens,we should prioritize samples stored within 1 year for molecular testing.Samples stored within 3 years can also meet the requirements of second-generation sequencing and other tests.Samples stored within 5 years can only be attempted to carry out PCR.Samples stored for more than 5 years were not recommended to carry out molecular tests.