Acute myeloid leukaemia secondary to treatment with capecitabine for metastatic colorectal cancer

EGFR-targeted bacteriophage lambda penetrates model stromal and colorectal carcinoma tissues, is taken up into carcinoma cells, and interferes with 3-dimensional tumor formation

Introduction

Colorectal cancer and other adult solid cancers pose a significant challenge for successful treatment because the tumor microenvironment both hinders the action of conventional therapeutics and suppresses the immune activities of infiltrating leukocytes. The immune suppression is largely the effect of enhanced local mediators such as purine nucleosides and eicosanoids. Genetic approaches have the promise of interfering with these mechanisms of local immunosuppression to allow both intrinsic and therapeutic immunological anticancer processes. Bacterial phages offer a novel means of enabling access into tissues for therapeutic genetic manipulations.

Methods

We generated spheroids of fibroblastic and CRC cancer cells to model the 3-dimensional stromal and parenchymal components of colorectal tumours. We used these to examine the access and effects of both wildtype (WT) and epidermal growth factor (EGF)-presenting bacteriophage λ (WT- λ and EGF-λ) as a means of delivery of targeted genetic interventions in solid cancers. We used both confocal microscopy of spheroids exposed to AF488-tagged phages, and the recovery of viable phages as measured by plaque-forming assays to evaluate access; and measures of mitochondrial enzyme activity and cellular ATP to evaluate the outcome on the constituent cells.

Results

Using flourescence-tagged derivatives of these bacteriophages (AF488-WT-λ and AF488-EGF-λ) we showed that phage entry into these tumour microenvironments was possible and that the EGF ligand enabled efficient and persistent uptake into the cancer cell mass. EGF-λ became localized in the intracellular portion of cancer cells and was subjected to subsequent cellular processing. The targeted λ phage had no independent effect upon mature tumour spheroids, but interfered with the early formation and growth of cancer tissues without the need for addition of a toxic payload, suggesting that it might have beneficial effects by itself in addition to any genetic intervention delivered to the tumour. Interference with spheroid formation persisted over the duration of culture.

Discussion

We conclude that targeted phage technology is a feasible strategy to facilitate delivery into colorectal cancer tumour tissue (and by extension other solid carcinomas) and provides an appropriate delivery vehicle for a gene therapeutic that can reduce local immunosuppression and/or deliver an additional direct anticancer activity.

Complex Chromosome-Positive Acute Myelogenous Leukemia Identified 16 Months following the Completion of Capecitabine Chemotherapy for Early-Stage Colon Cancer

Capecitabine is an oral chemotherapy that is used to treat several cancer types, including breast, gastrointestinal, hepatobiliary, and ovarian. The use of antimetabolites in cancer therapy has generally not been associated with leukemogenesis. In this report, we demonstrate a case of capecitabine-related acute myeloid leukemia that was diagnosed 16 months after the completion of treatment for early-stage colon cancer, by a complex chromosome analysis 48,XY,6,del(7)(q22),+8,+13,t(13;17)(q12;p13),t(13,21)(q12;122),+mar [Gazi Med J. 2018 Jan;29(1):57-58]. This is the first report to our knowledge of the development of t-AML in a patient with early-stage colon cancer that was caused by capecitabine. We should use capecitabine with caution. Further studies are essential to investigate capecitabine-triggered leukemogenesis.

Molecular and cytogenetic characteristics of myeloid malignancies following luminal gastrointestinal cancer

PURPOSE

Luminal gastrointestinal tract cancers (LGC) are common malignancies, and many patients can achieve long-term responses with surgery, cytotoxic and/or targeted therapies, and radiation. The long-term follow-up for patients with durable disease control has not been fully characterized, including subsequent malignancies. Such cases have not been comprehensively described.

PATIENTS AND METHODS

We identified patients evaluated for myeloid malignancies (MyM) who had a prior LGC at our institution over a 35-year period. Patient, disease, and treatment information was collected for analysis. Cytogenetic risk profiles were designated according to the Revised International Prognostic Scoring System for MDS and the European LeukemiaNet Guidelines for AML.

RESULTS

66 patients were included in our cohort with 71 prior LGC diagnoses, including three patients with multiple LGCs. 31 cases were treated with surgery alone, and 37 patients received chemotherapy. The median age at diagnosis of MyM was 71.8 years (range, 36.2-90.5), with median duration between initiation of treatment of LGC and diagnosis MyM of 7.9 years (range 0.005-38.8). Intermediate or adverse (AML)/poor-very poor (MDS) cytogenetic risk was common, occurring in 43% of MDS patients and 100% of AML patients; deletion 5q was the most common cytogenetic abnormality overall. DNMT3A mutations were the most common molecular alteration (6 patients with 7 mutations).

CONCLUSIONS

Among patients with MyM following LGC, a high proportion harbored cytogenetic changes, many of which were adverse or poor-risk. Deletion 5q and mutated DNMT3A were the most common abnormalities identified.

Myeloid malignancies after treatment for solid tumours

The cure rate for several solid tumour malignancies including breast cancers, head and neck cancers, bone cancers, and sarcoma has improved remarkably with the advent of neoadjuvant and adjuvant therapies. Unfortunately, exposure to chemotherapy or radiation as a part of these treatments exposes patients to the risk of subsequent myeloid malignancies. Therapy related myeloid malignancies have certain characteristic findings. They typically arise within 10 years of treatment exposure, they are seen in younger patients, and the greatest risk is in patients who receive therapy with alkylating agents or topoisomerase II inhibitors. Solid tumours whose therapies utilize these agents at higher doses, namely bone/soft tissue cancers, testicular cancer, anal cancer, and brain tumours, appear to be the groups at highest risk for T-MN. Beyond these patients, emerging populations diagnosed with T-MN include prior platinum exposure, and patients requiring G-CSF support with chemotherapy.

Molecular characterization of an MLL1 fusion and its role in chromosomal instability

Chromosomal rearrangements involving the mixed‐lineage leukemia (MLL1) gene are common in a unique group of acute leukemias, with more than 100 fusion partners in this malignancy alone. However, do these fusions occur or have a role in solid tumors? We performed extensive network analyses of MLL1‐fusion partners in patient datasets, revealing that multiple MLL1‐fusion partners exhibited significant interactions with the androgen‐receptor signaling pathway. Further exploration of tumor sequence data from TCGA predicts the presence of MLL1 fusions with truncated SET domain in prostate tumors. To investigate the physiological relevance of MLL1 fusions in solid tumors, we engineered a truncated version of MLL1 by fusing it with one of its known fusion partners, ZC3H13, to use as a model system. Functional characterization with cell‐based assays revealed that MLL1‐ZC3H13 fusion induced chromosomal instability, affected mitotic progression, and enhanced tumorsphere formation. The MLL1‐ZC3H13 chimera consistently increased the expression of a cancer stem cell marker (CD44); in addition, we detected potential collateral lethality between DOT1L and MLL1 fusions. Our work reveals that MLL1 fusions are likely prevalent in solid tumors and exhibit a potential pro‐tumorigenic role.

Secondary acute promyelocytic leukemia following chemotherapy for gastric cancer: A case report

Therapy-related acute myeloid leukemia (t-AML) refers to a heterogeneous group of myeloid neoplasms that develop in patients following extensive exposure to either cytotoxic agents or radiation. The development of t-AML has been reported following treatment of cancers ranging from hematological malignancies to solid tumors; however, to our knowledge, t-AML has never been reported following treatment of gastric cancer. In this study, we report the development of t-acute promyelocytic leukemia in a cT4N1M0 gastric cancer patient after an approximate 44 mo latency period following treatment with 4 cycles of oxaliplatin (OXP) (85 mg/m² on day 1) plus capecitabine (1250 mg/m² orally twice daily on days 1-14) in combination with recombinant human granulocyte-colony stimulating factor treatment. Karyotype analysis of the patient revealed 46,XY,t(15;17)(q22;q21)[15]/46,idem,-9,+add(9)(p22)[2]/46,XY[3], which, according to previous studies, includes some “favorable” genetic abnormalities. The patient was then treated with all-trans retinoic acid (ATRA, 25 mg/m²/d) plus arsenic trioxide (ATO, 10 mg/d) and attained complete remission. Our case illuminated the role of certain cytotoxic agents in the induction of t-AML following gastric cancer treatment. We recommend instituting a mandatory additional evaluation for patients undergoing these therapies in the future.

Influence of DNA damage and repair upon the risk of treatment related leukemia

Therapy-related myelodysplasia and acute myeloid leukemia (t-MDS/AML) are malignancies occurring after exposure to chemotherapy and/or radiotherapy. Several studies have addressed cumulative dose, dose intensity and exposure to specific agents of preceding cytotoxic therapy in relation to the risk of developing such leukemia. Since only a small percentage of patients exposed to cytotoxic therapy develop t-MDS/AML, it has been suggested that some genetic predisposition may be involved, specifically associated to polymorphisms in certain genes involved in chemotherapy/radiotherapy response - fundamentally genes intervening in drug detoxification and DNA synthesis and repair. A review is made of the genetic studies related to t-MDS/AML predisposition, focusing on the mechanistic findings of how specific chemotherapeutic drug exposure produces DNA damage and induces the chromosomal abnormalities characteristic of t-MDS/AML, the molecular pathways involved in repairing such drug induced damage, and the way in which they influence t-MDS/AML genesis. Specific issues are (a) the interaction of topoisomerase II inhibitors, alkylators and antimetabolite drugs with DNA repair mechanisms and their impact on t-MDS/AML leukemogenicity and (b) the influence of DNA polymorphisms in genes involved in DNA repair, drug metabolization and nucleotide synthesis, paying special attention to the relevance of folate metabolism. Finally, we discuss some aspects relating to study design that are most suitable for characterizing associations between drug exposure and genotypes related to t-MDS/AML risk - stressing the importance of the inclusion of chemotherapy-exposed control groups.