PCR‐based clonality analysis: a reliable method for the diagnosis and follow‐up monitoring of conservatively treated gastric B‐cell MALT lymphomas?

Publisher Website
Google Scholar
Abstract
Aims: We evaluated polymerase chain reaction (PCR) amplification of specific immunoglobulin heavy chain (IgH) gene rearrangements as a means of demonstrating monoclonality during follow‐up of conservatively treated gastric MALT lymphoma, and compared the reproducibility of PCR on sequential frozen and paraffin‐embedded endoscopic biopsies. We established an association between clonality detected by PCR and the histological observations.Methods and results: Sixty‐nine pairs of sequential frozen and paraffin‐embedded endoscopic biopsies from 21 conservatively treated patients were graded according to the Wotherspoon–Isaacson histological scoring system, which provides a measure of diagnostic confidence on a scale 0–5. PCR amplification of the IgH gene was performed using FR3/JH and FR2/JH primers. 68/69 paired samples (98.5%) showed identical mono‐ or polyclonal PCR amplification patterns. Forty‐seven out of 48 pairs of samples sharing similar histological features produced identical amplification patterns in both fresh and paraffin‐embedded tissues. In comparison with the histological grading, monoclonality was detected in 64.2% and 41.6% of samples scored 5 and 4, respectively. Conversely, among 64 samples scored 0–3, a monoclonal pattern was observed only in two samples, one of which was from a patient who relapsed 9 months later.Conclusions: PCR‐based clonality analysis by demonstration of specific IgH gene rearrangement can be easily and reliably performed on both frozen and paraffin‐embedded endoscopic biopsies. In conjunction with histological observation, this method can be used as a complementary tool to monitor MALT lymphoma regression during conservative treatment.