Real-Time Quantitative PCR Analysis of Amplified DNA on Chromosomes 4p15.2 and 6q23-24 from Formalin-Fixed, Paraffin-Embedded Breast Cancer Tissues

This study was performed to detect amplification of DNA sequences on chromosomes 4p15.2 and 6q23-24,obtained from formalin-fixed, paraffin-embedded, breast-cancer tissues. The prognostic relevance of theamplification was also demonstrated. DNA from formalin-fixed, paraffin-embedded tumor and correspondingnormal tissues of 53 patients with breast cancer was extracted and amplified by real-time quantitative PCRtechnique. Amplification of the DNA sequences on chromosomes 4p15.2 and 6q23-24 was detected in 23 (43%)and 32 (60%) cases, respectively. Thirty-six (68%) cases showed amplification on both or one of the chromosomes.These frequencies are similar to that obtained from fresh samples in our previous study. In addition, amplificationof the DNA on chromosomes 4p15.2 and / or 6q23-24 was predominantly observed in tumors with invasiveductal carcinoma. The findings in this study demonstrate that DNA extracted from formalin-fixed, paraffinembeddedbreast tumors can be used to determine amplification of DNA sequences on selective chromosomalregions. We also suggest that the amplified DNA on chromosomal regions 4p15.2 and 6q23-24 might be involvedin the development and progression of breast cancer.