Amplifications of AURKA and AURKB in a Burkitt lymphoma immunodeficiency-associated type: a case report

ABSTRACT In equatorial Brazil, the association of Burkitt lymphoma and Epstein–Barr virus manifests at high rates. Here, we report, for the first time, amplifications of aurora kinase genes (AURKA/B) in a patient with a history of periodontal abscess and the presence of a remaining nodule, diagnosed with Burkitt lymphoma and Epstein–Barr virus, and /HIV positive. The patient was a 38-year-old man who presented with a 2-week-old severe jaw pain and a 3-day-old severe bilateral headache. He had a history of human papilloma virus. Interphase FISH analysis showed AURKA and AURKB amplification. The patient’s condition worsened, progressing to death a month after the initial care. Changes in the MYCC and AURKA pathways are directly associated with genomic instability. Thus, MYCC rearrangements and higher expression of AURKA/B may be associated with therapy resistance, highlighting the importance of AURKA/B evaluation in Burkitt lymphoma.


❚ INTRODUCTION
Burkitt lymphoma (BL) is an aggressive B-cell malignancy that could be associated with the Epstein-Barr virus (EBV), with a frequency of 20-30% in the sporadic type and 25-40% in the immunodeficiency-associated type. Burkitt lymphoma represents a heterogeneous group of aggressive mature B-cell malignancies. (1) Burkitt lymphoma usually presents as a rapidly growing tumor and dissemination, with the primary tumor often found in the mesentery, testis, ovary, breast, kidney, and meninges. The involvement of lymph nodes, bone marrow, and the central nervous system is more common in patients with immunodeficiency. (2) Genetic changes commonly found in BL include chromosome translocation with 8q24 (MYCC) and 14q32 (IgH gene), 2p12 (Ig kappa), or 22q11 (Ig lambda). (1) Aurora kinase genes (AURKA and AURKB) play an important role in regulating the G2/M phase of the cell cycle and various mitotic events. (3) A correlation between the amplification of aurora kinase genes and clinical aggressiveness has been demonstrated in different types of neoplasms. (4) Given the aggressive response in the patient's evolution, amplifications of AURKA/B genes were investigated, which may have contributed to an unfavorable prognosis. We report an uncommon case of BL immunodeficiency-associated type, with EBV, and the amplification of aurora kinase genes, in a 38-year-old patient.

❚ CASE REPORT
A 38-year-old man presented to the stomatology department with a 2-week-old severe jaw pain. The patient had a history of periodontal abscess that was previously drained, resulting in the presence of a remaining nodule. In addition, the patient had a severe bilateral headache for 3 days. Seven days after the initial admission, the patient returned to the service, disoriented and in poor general condition, with frontal edema, throwing up, asthenia, and hyperoxia, without fever. The patient was referred for medical attention, and a physical examination revealed right iliac fossa pain, small-volume ascites, and a bilateral mediumvolume hydrocele. The patient was hospitalized for suspected pancreatitis.
He had a personal history of human papillomavirus (HPV), diagnosed in 2015, and HIV, diagnosed in 2016. The latest laboratory tests showed a TCD4+ lymphocyte count of 248 cells/µL and an undetectable viral load. The patient was under treatment with efavirenz/lamivudine/tenofovir. The follow-up VDRL, HCV, and HBV tests were negative until the last visit. A biopsy in the mesentery region revealed the presence of pleomorphic lymphocytes with evident nucleoli and macrophages with clear cytoplasm and a "starry sky" appearance ( Figure 1A). Immunohistochemistry was performed in an authorized diagnostic support service, revealing positivity for CD20, CD16, and BCL-6 proteins.
The patient had a progressive worsening of the clinical condition, progressing to death 1 month after the initial care. The patient signed a copy of the informed consent form, also signed by the main investigator, containing general information about the study and in accordance with the guidelines of the Ethics Committee (CAAE: 43920021.4.0000.5083; #4.675.519).

❚ DISCUSSION
Patients with BL usually display high-risk features compared to other B-cell malignancies. Endemic cases of BL are pathogenetically related to immune system disruption associated with infection by malaria and EBV. Conversely, the epidemic BL cases are associated with HIV infection, comprising 10-20% of the cases. (5) In this scenario, the interactions between EBV and HIV have been closely related to BL pathogenesis. From an epidemiological point of view, patients presenting the sporadic BL form, in association with EBV, are related to poverty rates. In Brazil, the association between BL and EBV infection is more common. Usually, patients present with a symptomatic stage associated with microbiological activation of B cells. (6) According to the literature, the presence of EBV confers a higher mutation rate in the lymphomagenesis process. Some data have demonstrated that EBVnegative BL arises from an early centroblast, while EBV-positive BL arises later in the development process from a memory B cell or late germinal center einstein (São Paulo). 2023;21:1-4 cell. (6) In addition, the gene expression signatures of these three variants appear to be distinct, and the expression of MYC is an almost-universal characteristic of BL. (7) In contrast, EBV-negative tumors usually present a mutation in the p53 pathway (75% of cases) that overcomes this tendency to undergo apoptosis, but these occur in only 30% of EBV-positive BL. (8,9) For the first time, we identified amplifications of aurora kinase genes (AURKA and AURKB) in the sample of a patient with BL who was EBV/HIV positive. Given the unavailability of fresh material for analyzing gene expression, we performed gene amplification using the iFISH technique. Amplifications were identified in all BL cells analyzed (n=50). Amplifications of AURKA/B genes are normally found in many epithelial cancers and hematological malignancies. Overexpression of these genes was shown to correlate with highly proliferative and malignant cancers, poor outcomes, and low survival rates. (10) The deregulation of AURKA/B activity or their expression in our patient may have resulted from the higher mutation rate during the lymphomagenesis process. However, it is necessary to mention that, given the patient's early death, assessing the response to treatment was impossible.
In addition, deregulation of AURKA/B activity may further promote genomic instability and drive the selection of other oncogenes (e.g., MYCC and TP53), which enhance tumor invasion and metastasis, as seen in our patient (brain metastasis). We must keep in mind that patients with BL frequently present with involvement of the abdominal organs, bone marrow, and nervous system. Tumor extension could also be associated with renal function impairment and lead to metabolic disorders. (11) In general, epidemic BL samples are characterized by low karyotypic complexity. (12) Although it was impossible to perform a classical cytogenetic study in our patient, there is a suspicion that he could have presented with a complex karyotype, given the AURKA/B amplifications. To support this, some years ago, we demonstrated that AURKA/B overexpression was associated with genomic instability in a cytogenetically stratified group (normal versus abnormal karyotype) of hematopoietic cells and bone marrow-derived mesenchymal stem cells from patients with myelodysplastic syndrome. (13) We also demonstrated a significant association between high expression of AURKA and cytogenetic profile in acute myeloid leukemia. (14) AURKA expression is independently associated with high WBC counts. In addition, most patients with acute myeloid leukemia with overexpressed AURKA and AURKB presented with complex karyotypes.

❚ CONCLUSION
This case report is the first attempt to establish a relationship between AURKA and AURKB expression in a patient with Burkitt lymphoma immunodeficiencyassociated type. Deregulation of the complex MYCC/ AURKA pathway is an important event leading to genomic instability through the bypass of the G2/M checkpoints. In Burkitt lymphoma cases, expressing abnormal MYCC levels and high expression of AURKA and AURKB might offer some resistance to conventional therapy. Thus, aurora kinase inhibitors may also be considered for this specific subgroup of Burkitt lymphoma, whose aggressive clinical course resembles high-grade lymphomas.