Expressions of the CagA protein and CagA-signaling molecules predict Helicobacter pylori dependence of early-stage gastric DLBCL.

We previously reported that early-stage gastric diffuse large B-cell lymphomas (DLBCLs), including DLBCLs with mucosa-associated lymphoid tissue (DLBCL[MALT]) and without ("pure" DLBCL) the features of MALT lymphomas, can achieve long-term complete remission after frontline Helicobacter pylori (HP) eradication (HPE). We recently reported that expression of cytotoxin-associated gene A (CagA) and CagA-signaling molecules (phospho-Src homology-2 domain-containing phosphatase [p-SHP2] and phospho-extracellular signal-regulated kinase [p-ERK]) is associated with HP dependence of gastric MALT lymphoma. However, the significance of CagA and CagA-signaling molecules in gastric DLBCL remains unexplored. The association between expression of CagA, p-SHP-2, and p-ERK in malignant B cells and tumor response to HPE was evaluated in 63 patients with stage IE/IIE1 HP-positive gastric DLBCL who received HPE as frontline treatment. We detected CagA expression in 20 of 42 DLBCL (MALT) cases (47.6%) and in 13 of 21 "pure" DLBCL cases (61.9%). CagA expression was higher in HP-dependent tumors than in HP-independent tumors (74.3% [26 of 35] vs 25.0% [7 of 28]). Patients with CagA expression responded to HPE quicker than those without expression (median time to complete remission, 4.0 months vs 5.0 months). The expression of CagA was closely associated with p-SHP-2 and p-ERK expression. Combined CagA, p-SHP-2, and p-ERK expression showed an increased positive predictive value (81.8% vs 75.9%) and an increased specificity (84.0% vs 75.0%) for HP dependence compared with CagA expression alone. Our results indicated that CagA and its signaling molecules can be detected in the malignant B cells of gastric DLBCL, and the expression of these molecules is clinically and biologically associated with HP dependence.

Overexpression of B cell-activating factor of TNF family (BAFF) is associated with Helicobacter pylori-independent growth of gastric diffuse large B-cell lymphoma with histologic evidence of MALT lymphoma.

We have recently demonstrated that nuclear expression of BCL10 predicts Helicobacter pylori (HP) independence of early-stage gastric diffuse large B-cell lymphoma (DLBCL) with histologic evidence of mucosa-associated lymphoid tissue (MALT). In this study, we examined the role of B cell-activating factor of TNF family (BAFF) in mediating BCL10 nuclear translocation and HP independence of gastric DLBCL (MALT). We used immunohistochemistry and immunoblotting to measure the expression of BAFF, pAKT, BCL3, BCL10, and NF-kappaB. Transactivity of NF-kappaB was measured by electromobility shift assay. In lymphoma samples from 26 patients with gastric DLBCL (MALT), we detected aberrant expression of BAFF in 7 of 10 (70%) HP-independent and in 3 of 16 (18.8%) HP-dependent cases (P = .015). BAFF overexpression was associated with pAKT expression (P = .032), and nuclear expression of BCL3 (P = .014), BCL10 (P = .015), and NF-kappaB (P = .004). In B-cell lymphoma Pfeiffer cells, BAFF activated NF-kappaB and AKT; the activated NF-kappaB up-regulated BCL10, and the activated AKT caused formation of BCL10/BCL3 complexes that translocated to the nucleus. Inhibition of AKT by LY294002 (a PI3K inhibitor) blocked BCL10 nuclear translocation, NF-kappaB transactivity, and BAFF expression. Our results indicate that autocrine BAFF signal transduction pathways may contribute to HP-independent growth of gastric DLBCL (MALT).

Maintenance BEZ235 Treatment Prolongs the Therapeutic Effect of the Combination of BEZ235 and Radiotherapy for Colorectal Cancer.

Our previous study demonstrated that administration of NVP-BEZ235 (BEZ235), a dual PI3K/mTOR inhibitor, before radiotherapy (RT) enhanced the radiotherapeutic effect in colorectal cancer (CRC) cells both in vitro and in vivo. Here, we evaluated whether maintenance BEZ235 treatment, after combinatorial BEZ235 + RT therapy, prolonged the antitumor effect in CRC. K-RAS mutant CRC cells (HCT116 and SW480), wild-type CRC cells (HT29), and HCT116 xenograft tumors were separated into the following six study groups: (1) untreated (control); (2) RT alone; (3) BEZ235 alone; (4) RT + BEZ235; (5) maintenance BEZ235 following RT + BEZ235 (RT + BEZ235 + mBEZ235); and (6) maintenance BEZ235 following BEZ235 (BEZ235 + mBEZ235). RT + BEZ235 + mBEZ235 treatment significantly inhibited cell viability and increased apoptosis in three CRC cell lines compared to the other five treatments in vitro. In the HCT116 xenograft tumor model, RT + BEZ235 + mBEZ235 treatment significantly reduced the tumor size when compared to the other five treatments. Furthermore, the expression of mTOR signaling molecules (p-rpS6 and p-eIF4E), DNA double-strand break (DSB) repair-related molecules (p-ATM and p-DNA-PKcs), and angiogenesis-related molecules (VEGF-A and HIF-1α) was significantly downregulated after RT + BEZ235 + mBEZ235 treatment both in vitro and in vivo when compared to the RT + BEZ235, RT, BEZ235, BEZ235 + mBEZ235, and control treatments. Cleaved caspase-3, cleaved poly (ADP-ribose) polymerase (PARP), 53BP1, and γ-H2AX expression in the HCT116 xenograft tissue and three CRC cell lines were significantly upregulated after RT + BEZ235 + mBEZ235 treatment. Maintenance BEZ235 treatment in CRC cells prolonged the inhibition of cell viability, enhancement of apoptosis, attenuation of mTOR signaling, impairment of the DNA-DSB repair mechanism, and downregulation of angiogenesis that occurred due to concurrent BEZ235 and RT treatment.

Helicobacter pylori CagA Translocation Is Closely Associated With the Expression of CagA-signaling Molecules in Low-grade Gastric Mucosa-associated Lymphoid Tissue Lymphoma.

We previously reported that the direct contact of Helicobacter pylori (HP) and B cells results in CagA translocation into the latter and that the translocated CagA regulates intracellular signaling pathways. Similarly, we recently found that CagA does exist in the malignant B cells of gastric mucosa-associated lymphoid tissue (MALT) lymphoma and that its presence is closely associated with HP dependence. In this study, we further evaluated whether CagA expression regulates signal transduction molecules in the tumor cells and further contributes to the lymphomagenesis of HP-dependent growth of gastric MALT lymphoma. Forty-seven patients with stage IE HP-positive gastric MALT lymphoma who received HP eradication as their frontline therapy were included. The expression of CagA and signaling pathway-related proteins, such as phospho-SHP-2 (p-SHP-2), p-ERK, p-p38 MAPK, Bcl-2, and Bcl-xL, in tumor cells was evaluated by immunohistochemistry. There were 25 HP-dependent and 22 HP-independent cases. We observed that the CagA expression rate was significantly higher in HP-dependent than in HP-independent tumors (72% [18/25] vs. 18.2% [4/22]; P<0.001). The expression of CagA was closely associated with p-SHP-2 (P=0.012), p-ERK (P=0.002), p-p38 MAPK (P=0.006), Bcl-2 (P=0.020), and Bcl-xL (P=0.006) expression. Spearman correlation coefficient analysis showed a strong correlation between CagA and signaling molecule expression. Combined CagA expression, p-SHP-2 expression, and p-ERK expression showed an increased positive predictive value (93.3% [14/15] vs. 81.8% [18/22]) and an increased specificity (95.5% [21/22] vs. 81.8% [18/22]) for HP dependence compared with CagA expression alone. Our results indicate that CagA protein expression is biologically relevant and is associated with the activation of its downstream signals in HP-dependent gastric MALT lymphoma.

t(11;18)(q21;q21) translocation as predictive marker for non-responsiveness to salvage thalidomide therapy in patients with marginal zone B-cell lymphoma with gastric involvement.

PURPOSE: Activation of TNF-α/NF-κB-related signaling pathway is crucial in sustain the growth of Helicobacter pylori-independent gastric mucosa-associated lymphoid tissue type (MALT) lymphoma. Thalidomide is an anti-angiogenic agent with anti-TNF-α and anti-NF-κB activity. This retrospective study evaluated the efficacy of thalidomide in standard therapy-failure gastric MALT lymphoma. METHODS: Between October 2003 and September 2007, 10 patients with antibiotics-resistant, chemotherapy-refractory gastric MALT lymphoma who received salvage thalidomide therapy at daily doses of 100-200 mg were identified from medical records and included. Status of t(11;18)(q21;q21) was determined by reverse transcriptase polymerase chain reaction for API2-MALT1 transcript, while expression of NF-κB was detected by immunohistochemistry. Tumor response was evaluated by RECIST criteria. RESULTS: Tumors were of stage IV in seven and IE/IIE-1 in three. The best tumor response after thalidomide was complete response in two and partial in three, with an overall response rate of 50% (95% confidence interval, 12.3-87.7%). At median follow-up of 39.3 months, the 3-year event-free and overall survival rates were 36.0% and 85.7%, respectively. API2-MALT1 transcript was detected in four (40%) tumors. Objective response rates of tumors with and without t(11;18)(q21;q21) were 0% (0/4) and 83% (5/6), respectively, P = 0.048 (Fisher's exact test). Thalidomide treatment was associated with significant down-regulation of nuclear NF-κB expression levels in residual neoplastic cells and microenvironments of responsive tumors, but not in t(11;18)(q21;q21)-positive, thalidomide-refractory tumors. CONCLUSIONS: Thalidomide is an effective salvage treatment for standard therapy-failure, t(11;18)(q21;q21) translocation-negative gastric MALT lymphoma and deserves further exploration.

Long-term follow-up of gastrectomized patients with mucosa-associated lymphoid tissue lymphoma: need for a revisit of surgical treatment.

BACKGROUND: Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is characterized by multifocality of the tumors, which often scatter over the mucosa of the stomach and adjacent upper gastrointestinal tract, and is therefore theoretically not curable by surgical resection. METHODS: We conducted a long-term follow-up study of 14 patients who received surgical treatment for gastric MALT lymphoma. Tissues from the surgical margins of the resected stomach were analyzed by polymerase chain reaction-based amplification of the complementarity-determining region 3 of the IgH gene for the presence of residual tumors. T (11;18)(q21;q21), a marker of Helicobacter pylori-independent MALT lymphoma, was analyzed by reverse transcription polymerase chain reaction. All living patients were restaged, and rebiopsied if suspicious lesions were identified. RESULTS: At a median follow-up of 11.5 years, only 1 patient had evidence of tumor recurrence. Three patients with molecularly proven residual tumors in the surgical margin remained disease-free at 9.6 to 11.6 years. Five patients with t(11;18)(q21;q21) in the tumor cells were disease-free at 9.2 to 12.6 years. CONCLUSION: Our results indicate that surgical resection is a highly curative treatment for gastric MALT lymphoma, even for patients with residual tumor cells in the surgical margins, and for patients with H. pylori-independent tumors. A revisit of surgical treatment for gastric MALT lymphoma is mandatory.

Nuclear expression of BCL10 or nuclear factor kappa B helps predict Helicobacter pylori-independent status of low-grade gastric mucosa-associated lymphoid tissue lymphomas with or without t(11;18)(q21;q21).

The t(11;18)(q21;q21) translocation is a specific marker for Helicobacter pylori-independent status of low-grade gastric mucosa-associated lymphoid tissue (MALT) lymphoma. However, there are no reliable markers to predict tumor response to H pylori eradication in patients without t(11;18)(q21;q21). Nuclear expression of BCL10 and nuclear factor kappa B (NF-kappaB) was recently found to be closely associated with H pylori-independent status of the high-grade counterpart of gastric MALT lymphoma, which usually lacks t(11;18)(q21;q21). This study examined whether these 2 markers can also predict H pylori-independent status of low-grade gastric MALT lymphomas without t(11; 18)(q21;q21). Sixty patients who underwent successful H pylori eradication for low-grade gastric MALT lymphomas were included. Forty-seven (78.3%) patients were negative for t(11;18)(q21;q21); among them, 36 (76.6%) were H pylori dependent and 11 (23.4%) were H pylori independent. Nuclear expression of BCL10 was significantly higher in H pylori-independent than in H pylori-dependent tumors (8 of 11 [72.7%] vs 3 of 36 [8.3%]; P < .001). Nuclear expression of NF-kappaB was also significantly higher in H pylori-independent than in H pylori-dependent tumors (7 of 11 [63.6%] vs 3 of 36 [8.3%]; P < .001). Further, nuclear translocation of BCL10 and NF-kappaB was observed in 12 of the 13 patients with t(11;18)(q21;q21), and all these 12 patients were H pylori independent. In summary, nuclear expression of BCL10 or NF-kappaB is predictive of H pylori-independent status of low-grade gastric MALT lymphoma with or without t(11;18)(q21; q21).