PB1803 THE RELATION BETWEEN HEPATITIS C INFECTION AND CELL OF ORIGIN (COO) OF DIFFUSE LARGE B‐CELL LYMPHOMA (DLBCL) AND THE PROGNOSTIC VALUE OF BOTH OF THEM (EGYPTIAN EXPERIENCE).

Background:COO has a significant prognostic impact on DLBCL outcome. HCV plays a great role in B‐cell proliferation and transformation to NHL.Aims:This study was conducted to emphasize the significance of COO classification of B‐NHL (DLBC) and its impact on survival. Also, to find out if there correlation between HCV infection and cell of origin in this type of lymphoma.Methods:This prospective study was held on 50 cases of DLBCL. DLBCL histopathological diagnosis was done by Hematoxylin and eosin–stained sections from formalin fixed, paraffin‐embedded tissue block for the tumor With CD20 stain to confirm the diagnosis of DLBCL according to the 2016 WHO classification. COO was detected by using Hans algorithm, by using the IHC expression of CD10, BCL6 and MUM (Hans et al, 2004) in paraffin‐embedded samples. RT PCR HCV RNA for chronic HCV infection was done for all patients. All patient received induction therapy with CHOP protocol in which 54 % of patients entered CR while the others were refractory.Results:The mean age of our patients was 55 years and 58% of them were female. Acoording to international prognostic index (IPI) about 36% of cases were low intermediate, 26% high intermediate, 20% were high IPI and only 8% were low. According to COO, about 68% of cases (34) were non GCB while only 32 % (16) were GCB. Our current study declared that 48% of patients (24) were positive to HCV and 52% (26) were negative. About 51.5% of non GCB cases were stage IV in correlation to only 35.5% in GCB cases with significant p value (p value = 0.002). Also, about 24 % of non GCB cases were high IPI in correlation to only 12 % in GCB although not significant. Also about 21 % of non GCB cases showed relapse in comparison to only 11.8 % in GCB with no significance. All of these result indicates that non GCB predicts dismal outcome in NHL.As regard correlation between survival and COO, GCB cases showed significantly prolonged PFS and OS (78, 88 months) in comparison to only (40.5, 31 months)) in non GCB (p value 0.054, 0.024). There was a significant correlation between HCV positivity and attaining CR (p value 0.025) in which 66.7% of HCV negative patients entered CR while only 34.8 % of HCV positive entered CR. Also HCV positive patients showed shortened PFS and OS (39, 28 months) in comparison to HCV negative cases (58,48) although not statistically significant. All of these indicates poor prognosis of HCV positivity in NHL. As regard correlation between HCV status and COO, about 25 % of GCB cases were HCV positive in comparison to only 58.8 % of non GCB cases were HCV positive. So, a significant correlation between HCV positivity and non GCB NHL was found (p value 0.026). In multivariate analysis, GCB, low and low intermediate IPI and CR achieving are considered an independent predictors of survival (p value 0.004, 0.015, 0.001).Summary/Conclusion:Hans algorithm is considered a good predicator of survival in B‐NHL. Also HCV positivity has a poor impact on outcome of NHL. There is possibly a correlation between HCV infection and cell of origin of lymphoma which needs further analysis and study.