Hi Gang...I never use this forum, but can't resist this one. I also agree with Dan Arber. The response he recieved about the 1994 Blood paper is misleading. At that time, the so-called SLVL collection in London had about 30% cases with t(11;14). We all know what these are!! Peter Isaacson told all of us at a meeting many years ago, related to his Blood paper on the histopathology of SLVL, that virtually all of these cases were MCLs. Thus, CD5 positivity in SLVL is likely impossible to interpret from the published literature. However, he also claimed to see CD5 infrequently and discussed in that paper the distinctions between PB flow and frozen-section Ipox. He also made note of variable phenotypes as cells move from one compartment to another! My best guess is that SLVL/HCL-variant etc is likely to be one of several choices. Most are likely MZLs of different types. We now know about CD5+ MALT lymphomas with a tendency to involve BM and likely blood as well (AJCP paper with Nancy Harris). Remember that Bill Pugh presented a small number of cases at US&CAP many years ago (before the Harris paper). If one looks at the cytogenetic data from the literature, it gets even more interesting. I came across several papers about HCL, HCL-variant etc, some of which had isolated del 7q31-32. This cytogenetic finding is almost certainly tightly connected to primary splenic marginal zone. I would guess that classical cytogenetics and/or other PCR-based approaches (how about taking such cases and CD5-negative ones and doing RT-PCR for the AP12-MLT rearrangement), together with gene expression data will likely help to clarify much of the confusion in the literature. Otherwise, this will continue to be a problem area because of the vagaries of PB morphology/interpretation and the reliance of so-called "signature" phenotypes. Moreover, PB morphology cannot be equated in anyway with histology in most of these cases. Are people surprized to know that MCL (Bcl-1 proven) are CD5-negative in 3% of cases!! Randy Gascoyne Randy D. Gascoyne Department of Pathology British Columbia Cancer Agency 600 W 10th Avenue Vancouver, BC Canada V5Z 4E6 Phone: (604) 877-6098, local # 2097 Fax: (604) 877-6178 E-mail: rgascoyn@bccancer.bc.ca
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