Detection of t(11;18)(q21;q21) by RT-PCR of the API2-MALT1 fusion transcript.
(A) Sensitivity of RT-PCR for detection of the API2-MALT1 fusion transcript. Tumor cells harboring t(11;18)(q21;q21) were serially diluted with tonsillar cells and were then subjected to RNA extraction and RT-PCR. Using the first set of PCR primers (API2-1 and MALT1), the API2-MALT1 fusion transcript was detectable when the t(11;18)(q21;q21)-positive cells were diluted down to a concentration of 1 in 106 tonsillar cells. M, molecular weight marker; Ton, tonsillar cell; 10−6 to 10−1, various tumor cell concentrations; T, undiluted tumor cells; −, negative control. (B) T(11;18)(q21;q21)-positive MALT lymphoma. The number corresponds to the case number in Table 2. −, negative control. (C) Case 16 shows an identically sized API2-MALT1 product between the primary gastric MALT lymphoma and the tumor-involved lymph node, spleen, and small intestine.
