Clinical cytology samples

Thirty-one residual LBC specimens collected from Kagoshima University Hospital, Japan, from 2014 to 2018, and six residual LBC samples from the Hokuto Hospital, Hokuto Social Medical Corporation in 2017, were used for the current study. The thirty-one samples from Kagoshima University Hospital were acquired during endoscopic retrograde cholangiopancreatography (ERCP). The six samples from Hokuto Hospital were taken by fine needle aspiration (FNA) from breast cancer tissues. The LBC specimens were fixed in approximately 5 mL CytoRich Red solution, and the residual samples were stored at 4°C for between 1 month and 4 years. The samples were processed for DNA extraction using the Maxwell Purification Kit, and DNA quality was confirmed as described above.