Detection of DNA by scraping the formalin-fixed paraffin-embedded tissue

Pakistan is a developing country and most of the research laboratories have limited required infrastructures for the diagnosis of cancer at molecular level. The polymerase chain reaction (PCR) on formalin-fixed paraffin-embedded tissues is becoming a popular procedure in the research centres. The study was conducted to introduce two new methods of DNA extraction for the PCR from formalin-fixed paraffin-embedded sections of surgical pathology specimens.

Two methods of DNA detection were used. In method A the formalin-fixed tissues were grossed, proper sections were taken, processed in an automatic tissue processor, embedded in paraffin blocks, and microtomic sections were made. In method B, the procedure was the same until embedding in the paraffin blocks, after which the selected paraffin blocks were set on a black card paper (4 cm x 4 cm) and 1 mg of pure scraped tissue was obtained using a scalpel, manually without using microtone.

DNA was successfully extracted but point mutation of p53 gene was not seen in SCP while it was determined in 96 and 93.75 per cent cases of SCC by method A and method B respectively. There was no statistical difference in the results by both methods (P = 0.359).

Scraping of the tissue for DNA detection was a simple method and may be performed in any laboratory. The reliability, reproducibility, and quality assurance of the present results are consistent with the already established techniques of DNA extraction for PCR.