Prognostic significance of immunoglobulin and T cell receptor gene rearrangements in patients with acute myeloid leukemia: Taiwan experience

Monitoring immunoglobulin heavy chain and T-cell receptor gene rearrangement in cfDNA as minimal residual disease detection for patients with acute myeloid leukemia

The present study aimed to examine whether monoclonal immunoglobulin heavy chain (IGH) or T-cell receptor (TCR) gene rearrangement in cell-free DNA (cfDNA) may be used for minimal residual disease (MRD) monitoring in patients with acute myeloid leukemia (AML). Monoclonal IGH and TCR rearrangement in cfDNA were monitored in patients with AML. A total of 94 (40%) patients had monoclonal IGH or TCR rearrangements in cfDNA at diagnosis; 84% of these patients (79 cases) achieved complete remission following 1–3 courses of induction chemotherapy. Among these cases, 89.9% were negative for monoclonal IGH or TCR rearrangement in cfDNA following consolidation chemotherapies. A total of 8 patients with consistently positive monoclonal IGH or TCR rearrangement in cfDNA relapsed within 6–10 months. During follow up, 39 patients demonstrated positive monoclonal IGH or TCR rearrangement in cfDNA and relapsed. Recurrence of monoclonal IGH or TCR rearrangement in cfDNA was observed 1–3 months earlier than bone marrow relapse and 11 patients with solitary extramedullary relapse demonstrated positive monoclonal IGH or TCR rearrangement recurrence in cfDNA. In conclusion, the detection of monoclonal IGH and TCR rearrangement in cfDNA may represent a useful tool for MRD monitoring in patients with AML.

Clinical observations on chemotherapy curable malignancies: unique genetic events, frozen development and enduring apoptotic potential

BACKGROUND

A select number of relatively rare metastatic malignancies comprising trophoblast tumours, the rare childhood cancers, germ cells tumours, leukemias and lymphomas have been routinely curable with chemotherapy for more than 30 years. However for the more common metastatic malignancies chemotherapy treatment frequently brings clinical benefits but cure is not expected. Clinically this clear divide in outcome between the tumour types can appear at odds with the classical theories of chemotherapy sensitivity and resistance that include rates of proliferation, genetic development of drug resistance and drug efflux pumps. We have looked at the clinical characteristics of the chemotherapy curable malignancies to see if they have any common factors that could explain this extreme differential sensitivity to chemotherapy.

DISCUSSION

It has previously been noted how the onset of malignancy can leave malignant cells fixed with some key cellular functions remaining frozen at the point in development at which malignant transformation occurred. In the chemotherapy curable malignancies the onset of malignancy is in each case closely linked to one of the unique genetic events of; nuclear fusion for molar pregnancies, choriocarcinoma and placental site trophoblast tumours, gastrulation for the childhood cancers, meiosis for testicular cancer and ovarian germ cell tumours and VDJ rearrangement and somatic hypermutation for acute leukemia and lymphoma. These processes are all linked to natural periods of supra-physiological apoptotic potential and it appears that the malignant cells arising from them usually retain this heightened sensitivity to DNA damage. To investigate this hypothesis we have examined the natural history of the healthy cells during these processes and the chemotherapy sensitivity of malignancies arising before, during and after the events. To add to the debate on chemotherapy resistance and sensitivity, we would argue that malignancies can be functionally divided into 2 groups. Firstly those that arise in cells with naturally heightened apoptotic potential as a result of their proximity to the unique genetic events, where the malignancies are generally chemotherapy curable and then the more common malignancies that arise in cells of standard apoptotic potential that are not curable with classical cytotoxic drugs.

Precursor B lymphoblastic leukemia 32 months after local therapy for a primary extramedullary myeloid cell tumor

A primary extramedullary myeloid cell tumor (pEMT) of an inguinal lymph node was completely excised without subsequent anti-tumor therapy in a 6-year-old child. Clinical observation and monitoring of blood and bone marrow (BM) did not reveal any pathologic results before 32 months, when a precursor B lymphoblastic leukemia was diagnosed. Identical T-cell receptor gamma rearrangement in nodal pEMT and in precursor B lymphoblastic leukemia in BM indicates a clonal relationship of these two tumors.

The comparative analysis of serum proteomes for the discovery of biomarkers for acute myeloid leukemia

OBJECTIVE

Acute myeloid leukemia (AML) develops as the consequence of a series of genetic changes in a hematopoietic precursor cell. However, the definitive diagnostic protein biomarkers for AML are still unclear. In our study to identify the biomarkers for an initial diagnosis, detection of relapse, and monitoring the minimal residual disease in AML by a less invasive method, serum proteins reflecting alterations in their proteomes were analyzed.

MATERIALS AND METHODS

We compared the two-dimensional electrophoresis patterns of human sera of 12 patients with AML with those of 12 normal subjects. The differentially expressed spots were identified by matrix-assisted laser desorption/ionization time-of-flight and electrospray ionization quadupole time-of-flight mass spectrometries.

RESULTS

Eight proteins that expressed differentially in the AML group were found. The expression levels of alpha-2-HS-glycoprotein, complement-associated protein SP-40, 40, RBP4 gene product, lipoprotein C-III, and an unknown protein were downregulated in serum of AML patients, whereas the other three proteins, including immunoglobulin heavy-chain variant, proteosome 26S ATPase subunit 1, and haptoglobin-1 were upregulated.

CONCLUSION

These results suggest that these proteins can be used as less invasive diagnostic and monitoring biomarkers of AML if further studies are done.

Identification of tumours with the CD43 only phenotype during the investigation of suspected lymphoma: a heterogeneous group not necessarily of T cell origin

AIMS

CD43 is usually employed as a T cell marker in the immunophenotypic work-up of suspected cases of non-Hodgkin's lymphoma (NHL). In this setting, tumours expressing CD43 in the absence of other T or B cell markers (CD43 only phenotype) are rare. We present four cases with this aberrant phenotype seen at our institution.

METHODS

The CD43 only phenotype was defined as expression of CD43 in the absence of expression of B cell markers CD20 and CD79a, and T cell markers CD3 and CD5, on initial immunohistochemistry performed on biopsies of suspected NHL. Combinations of further immunohistochemistry, flow cytometry, cytogenetic analysis and molecular studies were used to enable further diagnosis and lineage assignment.

RESULTS

The four cases were subsequently diagnosed as: one case of extramedullary acute myeloid leukaemia, one case of null cell anaplastic large-cell lymphoma, and two cases of extranodal diffuse large B cell lymphoma. None were demonstrated to be of T cell origin.

CONCLUSIONS

Our series further confirms the lack of specificity of CD43 expression for T cell lineage. Documentation of the CD43 only phenotype in suspected cases of NHL therefore requires further investigation to both correctly diagnose and clarify lineage of these tumours.