Cecília Correia

Multiple myeloma is a clonal plasma cell malignancy with a highly variable range of clinical manifestations. Over recent decades, substantial progress has been made in laboratory diagnostics, which has deepened our understanding of disease biology, improved risk stratification, and informed treatment strategies. In an era of transformation and innovation, conventional laboratory methods remain essential, as cutting-edge technologies might not be immediately accessible to all laboratories. Nonetheless, even widely used laboratory methodologies present many challenges, such as variability in assay performance, interpretative criteria, and standardization. This review by the Portuguese Multiple Myeloma Group of the Portuguese Society of Hematology provides a comprehensive overview and practical appraisal of current conventional laboratory methods employed for multiple myeloma diagnosis.

O mieloma múltiplo é uma neoplasia de plasmócitos que, na maioria dos casos, se associa à secreção de imunoglobulinas monoclonais e que pode cursar com um atingimento multiorgânico. O diagnóstico atempado do mieloma múltiplo é essencial para evitar ou limitar danos irreversíveis e disfunção dos órgãos-alvo. A apropriada estratificação inicial dos doentes permite otimizar a seleção e a sequência da terapêutica, assim como o correto seguimento durante o tratamento, com impacto na sobrevivência. As presentes recomendações laboratoriais do Grupo Português do Mieloma Múltiplo oferecem orientações para o diagnóstico e seguimento laboratorial dos doentes com mieloma múltiplo. O seguimento e diagnóstico de doentes com outras gamapatias monoclonais de significado clínico não foram incluídos neste texto. A sua elaboração tem por base orientações internacionais, publicações científicas e experiência de um painel de especialistas nacionais das áreas clínicas e laboratoriais dedicados ao estudo e tratamento do mieloma múltiplo.

Most patients with chronic myeloid leukemia (CML) treated with tyrosine kinase inhibitors (TKIs) will relapse if treatment is withdrawn, but various trials have recently demonstrated that a significant proportion of patients who achieved a stable and deep molecular response (DMR) can stop therapy without relapsing. However, most information on treatment cessation was obtained from clinical trials with strict recruiting criteria. We evaluated the outcome of 25 patients with CML that discontinued TKI therapy in our institute in real-world clinical practice. Of the 25 patients, 76% discontinued therapy in sustained deep molecular response (SDMR) and 24% were in unsustained DMR (UDMR). Discontinuation of therapy due to adverse effects was observed in 5 and 50% of the patients in the SDMR and UDMR groups, respectively. After TKI discontinuation, patients were followed for a median of 24 months. At the time of this analysis, 56% patients had a molecular relapse after a median of 4 months. SDMR and longer treatment duration were associated with lower probability of molecular relapse: 25% in SDMR patients with TKI treatment > 96 months and 85% in UDMR patients with TKI treatment ≤96 months. All relapsed patients promptly resumed TKI therapy and regained at least major molecular response (MMR). Our results suggest that TKI discontinuation is safe outside clinical trials and particularly effective in CML patients who are in SDMR with longer TKI treatment duration.

Atypical BCR-ABL1 transcripts are detected in less than 5% of patients diagnosed with chronic myeloid leukaemia (CML), of which e19a2 is the most frequently observed, with breakpoints in the micro breakpoint cluster region (μ-BCR) and coding for the p230 BCR-ABL1 protein. p230 CML is associated with various clinical presentations and courses with variable responses to first-line imatinib. Here we report a case of imatinib resistance due to an E255V mutation, followed by early post-transplant relapse with a T315I mutation that achieved a persistent negative deep molecular response (MR5.0) after treatment with single-agent ponatinib. Using CastPCR, we could trace back the presence of the T315I mutation to all the RNA samples up to the detection of T315 mutation by Sanger sequencing shortly after allogeneic hematopoietic stem cell transplantation (HSCT). This case illustrates the major interest of ponatinib as a valid treatment option for e19a2 CML patients who present a T315I mutation following relapse after HSCT.

Prostate carcinomas harboring 8q gains are associated with poor clinical outcome, but the target genes of this genomic alteration remain to be unveiled. In this study, we aimed to identify potential 8q target genes associated with clinically aggressive prostate cancer (PCa) using fluorescence in situ hybridization (FISH), genome‐wide mRNA expression, and protein expression analyses. Using FISH, we first characterized the relative copy number of 8q (assessed with MYC flanking probes) of a series of 50 radical prostatectomy specimens, with available global gene expression data and typed for E26 transformation specific (ETS) rearrangements, and then compared the gene expression profile of PCa subsets with and without 8q24 gain using Significance Analysis of Microarrays. In the subset of tumors with ERG fusion genes (ERG+), five genes were identified as significantly overexpressed (false discovery rate [FDR], ≤5%) in tumors with relative 8q24 gain, namely VN1R1, ZNF417, CDON, IKZF2, and NCOA2. Of these, only NCOA2 is located in 8q (8q13.3), showing a statistically higher mRNA expression in the subgroup with relative 8q gain, both in the ERG+ subgroup and in the whole series (P = 0.000152 and P = 0.008, respectively). Combining all the cases with NCOA2 overexpression, either at the mRNA or at the protein level, we identified a group of tumors with NCOA2 copy‐number increase, independently of ETS status and relative 8q24 gain. Furthermore, for the first time, we detected a structural rearrangement involving NCOA2 in PCa. These findings warrant further studies with larger series to evaluate if NCOA2 relative copy‐number gain presents prognostic value independently of the well‐established poor prognosis associated with MYC relative copy‐number gain.

Background: NUP98 gene rearrangements have been reported in acute myeloid leukemia, giving rise to fusion proteins that seem to function as aberrant transcription factors, and are thought to be associated with poor prognosis. Findings: A patient with treatment-related acute myeloid leukemia presented a t(3;11)(p11;p15) as the only cytogenetic abnormality. FISH and molecular genetic analyses identified a class 1 homeobox gene, POU1F1, located on chromosome 3p11, as the fusion partner of NUP98. In addition, we have found that the patient harbored an FLT3-ITD mutation, which most likely collaborated with the NUP98-POU1F1 fusion gene in malignant transformation. Conclusions: We have identified POU1F1 as the NUP98 fusion partner in therapy-related AML with a t(3;11)(p11;p15). This is the first POU family member identified as a fusion partner in human cancer.

Chromosomal rearrangements affecting the MLL gene are associated with high‐risk pediatric, adult and therapy‐associated acute leukemia. In this study, conventional cytogenetic, fluorescence in situ hybridization, and molecular genetic studies were used to characterize the type and frequency of MLL rearrangements in a consecutive series of 45 Portuguese patients with MLL‐related leukemia treated in a single institution between 1998 and 2011. In the group of patients with acute lymphoblastic leukemia and an identified MLL fusion partner, 47% showed the presence of an MLL–AFF1 fusion, as a result of a t(4;11). In the remaining cases, a MLL–MLLT3 (27%), a MLL–MLLT1 (20%), or MLL–MLLT4 (7%) rearrangement was found. The most frequent rearrangement found in patients with acute myeloid leukemia was the MLL–MLLT3 fusion (42%), followed by MLL–MLLT10 (23%), MLL–MLLT1 (8%), MLL–ELL (8%), MLL–MLLT4 (4%), and MLL–MLLT11 (4%). In three patients, fusions involving MLL and a septin family gene (SEPT2, SEPT6, and SEPT9), were identified. The most frequently identified chromosomal rearrangements were reciprocal translocations, but insertions and deletions, some cryptic, were also observed. In our series, patients with MLL rearrangements were shown to have a poor prognosis, regardless of leukemia subtype. Interestingly, children with 1 year or less showed a statistically significant better overall survival when compared with both older children and adults. The use of a combined strategy in the initial genetic evaluation of acute leukemia patients allowed us to characterize the pattern of MLL rearrangements in our institution, including our previous discovery of two novel MLL fusion partners, the SEPT2 and CT45A2 genes, and a very rare MLL–MLLT4 fusion variant.

Acute megakaryoblastic leukemia (AMKL) with t(1;22)(p13;q13) is a subset of acute myeloid leukemia (AML) representing RBM15–MKL1 fusion transcript was detected by RT‐PCR and confirmed by sequencing analyses. FISH analyses revealed the presence of the four‐way translocation t(1;22;17;18)(p13;q13;q22;q12). Pediatr Blood Cancer 2011;56:846–849.

Background: Abnormalities of 11q23 involving the MLL gene are found in approximately 10% of human leukemias. To date, nearly 100 different chromosome bands have been described in rearrangements involving 11q23 and 64 fusion genes have been cloned and characterized at the molecular level. In this work we present the identification of a novel MLL fusion partner in a pediatric patient with de novo biphenotypic acute leukemia. Methods: Cytogenetics, fluorescence in situ hybridization (FISH), molecular studies (RT-PCR and LDI-PCR), and bioinformatic sequence analysis were used to characterize the CT45A2 gene as novel MLL fusion partner in pediatric acute leukemia. Results: Fluorescence in situ hybridization of bone marrow G-banded metaphases demonstrated a cryptic insertion of 11q23 in Xq26.3 involving the MLL gene. Breakpoint fusion analysis revealed that a DNA fragment of 653 kb from 11q23, containing MLL exons 1-9 in addition to 16 other 11q23 genes, was inserted into the upstream region of the CT45A2 gene located at Xq26.3. In addition, a deletion at Xq26.3 encompassing the 3' region of the DDX26B gene (exons 9-16) and the entire CT45A1 gene was identified. RNA analysis revealed the presence of a novel MLL-CT45A2 fusion transcript in which the first 9 exons of the MLL gene were fused in-frame to exon 2 of the CT45A2 gene, resulting in a spliced MLL fusion transcript with an intact open reading frame. The resulting chimeric transcript predicts a fusion protein where the N-terminus of MLL is fused to the entire open reading frame of CT45A2. Finally, we demonstrate that all breakpoint regions are rich in long repetitive motifs, namely LINE/L1 and SINE/Alu sequences, but all breakpoints were exclusively identified outside these repetitive DNA sequences. Conclusion: We have identified CT45A2 as a novel spliced MLL fusion partner in a pediatric patient with de novo biphenotypic acute leukemia, as a result of a cryptic insertion of 11q23 in Xq26.3. Since CT45A2 is the first Cancer/Testis antigen family gene found fused with MLL in acute leukemia, future studies addressing its biologic relevance for leukemogenesis are warranted.