Comparison between real-time quantitative PCR detection of HER2 mRNA copy number in peripheral blood and ELISA of serum HER2 protein for determining HER2 status in breast cancer patients.
BACKGROUND
The development of non-invasive procedure to determine HER2 status may represent a powerful method for monitoring disease progression and response to the treatment.


METHODS
Serum samples and RNA from peripheral blood were evaluated in 85 breast cancer patients (49 HER2 positive and 36 HER2 negative) and 22 healthy controls. HER2 mRNA levels were measured by real-time quantitative PCR (QPCR) and serum HER2 protein by immunoenzimatic assay (EIA). ROC curve analyses were used to determine the optimal cut off values.


RESULTS
A statistically significant difference was detected for both QPCR and EIA in HER2 positive patients as compared with both healthy controls and HER2 negative tumours. QPCR showed a 91% (CI95%: 84%-98%) specificity and a 78% (CI95%: 68%-88%) sensitivity for an optimal cut off value of 4.74. The optimal cut off value for EIA was 22 ng/ml yielding a 95% (CI95%: 90%-100%) specificity and a 59% (CI95%: 48%-70%) sensitivity. The QPCR assay was slightly less specific than EIA in discriminating HER2 positive breast cancers from HER2 negative tumours (78% CI95%: 69%-87% versus 86% CI95%: 79%-93%), but it was more sensitive (76% CI95%: 67%-85% versus 55% CI95%: 44%-66%).


CONCLUSIONS
Our results indicate that QPCR performs better than EIA in the determination of HER2 status of breast cancer patients and could be useful in monitoring the disease during follow up.
Savino
Maria
M
Clinical Analysis Laboratory, CSS Hospital, IRCCS, San Giovanni Rotondo (FG), Italy. mg.savino@operapadrepio.it
Parrella
Paola
P
Copetti
Massimiliano
M
Barbano
Raffaela
R
Murgo
Roberto
R
Fazio
Vito Michele
VM
Valori
Vanna Maria
VM
Carella
Massimo
M
Garrubba
Maria
M
Santini
Stefano Angelo
SA
D000328:Adult; D001943:Breast Neoplasms / Q000097:blood* / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D016022:Case-Control Studies; D018450:Disease Progression; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D018628:Gene Dosage; D006801:Humans; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods*; D012333:RNA, Messenger / Q000097:blood / Q000235:genetics; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000097:blood* / Q000235:genetics* / Q000378:metabolism
D012333:RNA, Messenger; D018719:Erb-b2 Receptor Tyrosine Kinases