Luthra, Rajyalakshmi

Abstract Abstract 2926 Background: RAS proteins are encoded by 3 proto-oncogenes (K-RAS, N-RAS, and H-RAS) and regulate the growth and differentiation of many cellular types, including the myeloid compartment. Codons 12, 13, and 61 (in N-RAS and K-RAS) have been reported to be common targets of mutations. These mutations result in constitutive activation of the RAS pathway by increasing intracellular RAS GTP levels, which result in activation of the RAS/MEK and the RAS/PI3K pathways. Its prognostic significance in MDS is yet to be clarified. Because the potential prognostic and therapeutic implications of RAS mutations in MDS, we decided to study the impact of RAS mutations in patients (pts) with MDS. Methods: Mutation analysis of KRAS and NRAS codons 12, 13, and 61 was performed by Pyrosequencing using biotinylated reverse primers. All pts referred to MD Anderson between 2000–2009 were reviewed. In addition to standard clinical characteristics, including karyotyping, mutational status of Flt3, c-Kit and JAK2 was also analyzed. Overall survival was calculated based on Kaplan-Meier. Results: Of the 1067 pts with MDS of age above 17 evaluated for RAS mutation, 43 pts (4%) were positive. Seventy nine percent of RAS mutations were of N-RAS type (codon12 (55%), codon 13 (12%), codon 61(12%)) with K-RAS 12 comprising the rest (21%). Median age was 68 years (range, 18–94) with 66% being males (703 pts). Their median white blood cell (WBC) was 3.3×109/L (range, 0.3–72.2), hemoglobin 9.8 (range, 3–17.5), and platelets 73×109/liter (range, 1–1040). Median bone marrow blast was 5% and 77 pts (7%) had leukemic transformation. More than half of the pts had RAEB or RAEB-t (44% and 9 % respectively) which translated into fewer patients in the low IPSS category (19%). The median age was 66 years (range 26–84) in the RAS mutated (muRAS) group compared to 68 in the wild type (wtRAS). WBC was higher in the muRAS group compared to wtRAS (6.8 ×109/L vs. 3.2 ×109/L, p<0.001 by Mann-Whitney median test (M-W-T)). Percent of bone marrow blasts was higher (9%) in muRAS group compared to 5% in wtRAS (p<0.001 by M-W-T). High (Int-2 and high) risk by IPSS was more frequent in muRAS 51% compared to 40% in wtRAS group (p=0.11). Leukemic transformation was 9% and 7% (p=0.61) in both muRAS and wtRAS groups respectively. RAS mutation was detected more frequently in the CMML subgroup (12/80 (15%) pts). There were no differences in terms of response to DNA methylating inhibitors (CR in 41% in muRAS versus 40% in wtRAS). ARA-C-based regimens resulted in better CR in wtRAS than muRAS (59% vs 25%); however, the size of muRAS group was too small (1 out 4 pts).There was a trend towards shorter overall survival (OS) in the muRAS group compared to wtRAS (395 vs. 500 days, p value=0.057). MuRAS RAEB (325 vs. 450 days, p= 0.13) and RAEB-t (125 vs. 375 days, p= 0.27) subgroups showed a trend towards worse OS compared to wtRAS group. There was a significant OS decrease in RCMD (150 vs. 700 day, p= 0.015). Surprisingly, muRAS CMML group showed a trend towards better OS compared to wtRAS (728 vs. 687 days, p=0.44). Additionally we analyzed patients for presence of Flt3 mutation. These were present in only 18 of the pts (4%) but none of them had also a RAS mutation. There was no c-Kit mutations found in this cohort of pts, compared to 9/37 (24%) pts tested positive for JAK2V617F. Conclusion: MuRAS occurs in 4% of pts with MDS. In the muRAS group, pts tended to have higher risk disease and risk of transformation to acute leukemia compared with wtRAS. OS tended to be worse in some subgroups in muRAS. Although the prognostic impact of RAS mutations in MDS appears to be limited, mutations could be used to develop targeted therapeutic interventions. Disclosures: No relevant conflicts of interest to declare.

6010 Background: An evolutionary action scoring algorithm (EAp53) based on phylogenetic sequence variations and speciation stratifies head and neck squamous cell carcinoma (HNSCC) patients bearing TP53 missense mutations as high-risk (high, EAp53≥75), associated with poor outcomes, or low-risk (low), with similar outcomes as TP53 wild-type (wt), and has been validated as a reliable prognostic marker. This study is designed to further validate prior findings that EAp53 is a prognostic marker for locally advanced HNSCC patients, and assess its predictive value for treatment outcomes to adjuvant bio-chemoradiotherapy. Methods: Eighty one resection specimens from patients treated surgically for stage III or IV human papillomavirus-negative (HPV(-)) HNSCC with high-risk pathologic features, who received either Arm 1) radiotherapy(RT)+cetuximab(CTX)+cisplatin or Arm 2) RT+CTX+docetaxel, as adjuvant treatment in a phase II randomized clinical trial (RTOG 0234) underwent TP53 targeted sequencing, and EAp53 scoring. The EAp53 scores were correlated with clinical outcomes. Due to limited sample sizes, patients were combined into 2 EAp53 groups: wt/low and high/other. Results: At median follow-up of 10 years, there was a significant interaction between treatment and EAp53 group for overall survival (OS) (p = 0.008), disease-free survival (DFS) (p = 0.05) and distant metastasis (DM) (p = 0.004). Within arm 2, high/other showed worse OS [HR 4.69 (1.52-14.50)], DFS [HR 2.69 (1.16-6.21)], and had higher DM [HR 11.71 (1.50-91.68)] than wt/low. Within arm 1, there was no significant difference by EAp53 in OS, DFS and DM. Within the wt/low group, arm 2 had better OS [HR 0.11 (0.03-0.36)], DFS [HR 0.24 (0.09-0.61)], and DM [HR 0.04 (0.01-0.31)] than arm 1 but this was not found in high/other. Conclusions: High/other EAp53 scores were associated with worse survival for patients in arm 2. Arm 2 is associated with better survival than arm 1 for patients with wt/low EAp53. This benefit appears to be largely driven by a reduction in DM. Further validation is required to determine whether EAp53 can be used for personalized post-operative treatment decisions in HPV(-) HNSCC.

Abstract The t(14;19)(q32;q13) involving the IGH@ and BCL3 loci is an infrequent cytogenetic abnormality detected in B-cell malignancies. We describe the clinicopathologic, cytogenetic, and molecular genetic characteristics of 14 cases of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) with t(14;19)(q32;q13). All patients (10 men and 4 women) had lymphocytosis; 10 had lymphadenopathy. Blood and bone marrow lymphocytes were predominantly small, but cytologically and immunophenotypically atypical. In all cases, t(14;19) was found in the neoplastic stem line; it was the sole abnormality in 4. Ten cases showed additional cytogenetic abnormalities, including trisomy 12 in 9 and complex karyotypes in 7. Fluorescence in situ hybridization demonstrated IGH@/BCL3 fusion gene in all cases. In all cases, the IGHV genes were unmutated, but only 7 expressed ZAP70. Seven cases preferentially used IGHV4-39. Our results indicate that t(14;19)(q32;q13) identifies a subset of CLL/SLL with distinctive clinicopathologic and genetic features. Furthermore, t(14;19) may represent an early, possibly primary, genetic event.

Abstract The t(2;14)(p16;q32) has been reported previously in only 12 cases of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). The clinicopathologic features have been incompletely described. We describe 6 new cases of CLL/SLL with t(2;14)(p16;q32). All had marrow involvement, 4 had absolute lymphocytosis, 4 had lymphadenopathy, and 3 had hepatosplenomegaly. All showed atypical lymphocyte morphologic features with plasmacytoid differentiation and irregular nuclei; 3 had increased prolymphocytes. Flow cytometry demonstrated typical immunophenotypes in 5 and an atypical immunophenotype in 1. All expressed ZAP70; 5 assessed showed unmutated IgVH genes. Karyotyping identified t(2;14)(p16;q32) as the sole abnormality in 1, primary abnormality in 2, and part of a complex karyotype in 3. Fluorescence in situ hybridization analysis revealed BCL11A/IgH rearrangement in all. After chemotherapy, 3 patients died of disease and 3 were alive with disease (median follow-up, 80 months). We conclude that CLL/SLL with t(2;14) (p16;q32) and BCL11A/IgH rearrangement is characterized by atypical morphologic features and unmutated IgVH genes.