The Detection of Circulating Breast Cancer Cells in Peripheral Blood by Reverse Transcriptase-Polymerase Chain Reaction

Aug 26, 2026

A reverse transcriptase-polymerase chain reaction (RT-PCR) approach was used to identify circulating breast cancer cells in venous blood before surgery and to evaluate cytokeratin-19 (CK-19) and cytokeratin-20 (CK-20) as target mRNA markers. CK-19 mRNA was detected in all samples from healthy donors and breast cancer patients, providing no diagnostic value for circulating cancer-cell detection. CK-20 mRNA was absent in healthy donor blood but was found in 23% of patients, without correlation to stage or axillary lymph node status. CK-20 served as an useful marker for detecting circulating cancer cells.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages5

Reading Time13 min

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INTRODUCTION

Prognostic value of axillary node metastasis

Rationale for detecting circulating tumor cells

RT-PCR and cytokeratin mRNA markers

MATERIALS AND METHODS

Blood preparation

Total RNA isolation

RT-PCR

Statistical analysis

# The Detection of Circulating Breast Cancer Cells in PeripheralBlood by Reverse Transcriptase-Polymerase Chain Reaction Some circulating cancer cells in the blood play a central role in the metastaticprocess and may have a major influence on patient progress.Their numberscan be very small and techniques for their detection need to be both sensitiveand specific.Polymerase chain reaction(PCR)has been successfully used todetect small numbers of tumor cells in cancer.We used a reverse transcriptase-polymerase chain reaction (RT-PCR)to detect circulating breast cancer cellsin venous blood samples before operations and assessed cytokeratin-19 (CK- Jeoung Won Bae,Kwang Ho Choi,Han Gyum Kim*,Seol Hee Park Departments of Surgery and Pathology*,KoreaUniversity College of Medicine,Seoul,Korea Received:3 November 1999 Accepted:7 January 2000 Address for correspondence Jeoung Won BaeM.D. Department of General Surgery,Korea UniversityCollege of Medicine,126-1,Anam-dong 5-ga,Sungbukgu Seoul 136-705,KoreaTel:+82.2-920-5978,Fax:+82.2-928-9231E-mail:kujwbae@unitel.co.kr 19)and cytokeratin-20(CK-20)as target mRNA markers in the blood of healthydonors(n=6)and breast cancer patients(n=30)with American Joint Committeeon Cancer stages 0 to Illa.CK-19 mRNA was expressed in allblood samplesof healthy donors and patients.But CK-20 was the only mRNA marker notdetected in the blood from healthy donors.Seven of 30 (23%)venous bloodisolates of breast cancer patients yielded a CK-20 mRNA with positive results.There was no correlating CK-20 mRNAexpression with stage and axillary lymphnode status.In conclusion,CK-19 showed no diagnostic value as a mRNAmarker in the detection of circulating cancer cells by RT-PCR assay becausethis was expressed in the blood of healthy donors.CK-20 mRNA was an usefulmarker to detect circulating cancer cells in breast cancers. Key Words:Breast Neoplasms;Keratin;Reverse Transcriptase Polymerase Chain Reaction ## INTRODUCTION In patients with operable breast cancer,the numberof axillary nodes with metastases is an important prog-nostic factor that allows selection of those who mightbenefit from adjuvant medical treatment(1).But,otherthan lymph node metastases,prognostic factors that sug-gest high probability of recurrence and need for adjuvanttherapy have not been well established (2).Breast cancerhas been accepted by many investigators as a systemicdisease(3,4).Thus,the detection of circulating tumorcells in the peripheral blood of breast cancer patients maybe a major factor that influences their prognosis.Serialsectioning and immunohistochemistry staining of axillarylymph nodes in breast cancer patients have increased thedetection of micrometastases ranging from 9%to 33% (5).However,immunohistochemistry despite having thesensitivity to detect 1 tumor cell in 10⁵to 10⁶normalcells is very labor-intensive and has a limited specificitydue to a specific antigen expression.Recently,reversetranscriptase-polymerase chain reaction(RT-PCR)has been developed as an ultrasensitive method (sensitivity:1 cancer cell in 10 normal cells)to detect micrometas-tases in peripheral blood of patients with breast cancer(6-9)and various epithelial cell cancers(10).In breastcancer,Datta et al.(11)have developed a method basedon RT-PCR amplification of cytokeratin mRNA fordetection. In this study,we detected the circulating cancer cellswith CK-19 and CK-20 as mRNA markers in the peri-pheral blood of patients with varying stages of breastcancers using RT-PCR.Then we assessed the usefulnessof CK-19 or CK-20 as a target mRNA marker. ## MATERIALS AND METHODS Blood preparation Peripheral blood was obtained from 6 healthy femaledonors and 30 breast cancer patients without evidenceof distant metastasis and who were operated at Korea Circulating Breast Cancer Cells University Hospital in 1998.Ten milliliters of peripheralblood was sampled at the ante-cubital vein prior tosurgery. ## Total RNA isolation 0.5 mL of blood samp

FAQs

Why is detecting circulating breast cancer cells important?

Circulating tumor cells may influence prognosis and recurrence risk, complementing traditional prognostic factors such as axillary node metastases.

How were CK-19 and CK-20 evaluated in venous blood?

RT-PCR was used to detect CK-19 and CK-20 mRNA in peripheral blood isolates from healthy donors and breast cancer patients prior to surgery.

What was the main finding about CK-19 and CK-20 as markers?

CK-19 mRNA was expressed in both healthy donors and patients, so it lacked diagnostic value. CK-20 mRNA was not detected in healthy donors and was positive in 23% of patients, making it useful for detection.

Aug 26, 2026

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