Feasibility and limitations of cultured skin fibroblasts for germline genetic testing in hematologic disorders

To avoid acquired variants found in the blood, cultured skin fibroblasts are a recommended DNA source for germline genetic testing in patients with hematologic disorders, but data are lacking regarding practicality and limitations. We conducted a retrospective cohort study of 350 subjects with hematologic disorders who underwent skin fibroblast culture for germline genetic testing. We analyzed next-generation sequencing data from the targeted capture of 144 inherited cancer and bonemarrow failure genes to identify variants at heterozygous and subclonal variant allele frequencies. Sixteen (5%) biopsies failed to culture. Culture failure was more likely in samples with delays in culture initiation (OR = 4.3; p < 0.01) or a pathogenic variant in a telomere gene (OR = 42.6; p < 0.01). Median culture time was 28 days (IQR 22-29 days). Culture time was longer for subjects with prior allogeneic stem cell transplantation (+10.7%; p = 0.02) and shorter in subjects with a heterozygous pathogenic variant (-11.9%; p < 0.01), larger biopsy size (-10.6%; p < 0.01), or lymphoid malignancy (-8.4%; p < 0.01). Subclonal variants were identified in 10 (4%) and confirmed in five (56%) of eight with alternate samples available. Subclonal and discordant variants illustrate that germline testing from cultured skin fibroblasts requires phenotypic correlation and, in rare cases, follow-up studies for optimal interpretation.

Somatic mutation panels: Time to clear their names

With improvements in DNA sequencing technologies and the consequent reduction in costs, next generation sequencing is being utilized increasingly in panel-based testing to perform molecular profiling of tumors. Such tumor-based panels are often referred to as 'somatic' panels, but this term is misleading and should not be used, since not all DNA variants within a tumor are somatic in nature. Every cell in a person's body contains that person's germline DNA, including tumor cells. Moreover, tumor samples are invariably contaminated with blood, a tissue that can contain somatic mutations itself in a process now called clonal hematopoiesis. Differentiating between germline variants or tumor-associated somatic mutations versus clonal hematopoiesis can be challenging. In this review, we address how to interpret the results of somatic mutation panels, how to differentiate between germline and truly somatic events, and discuss the importance of this distinction.

Deletion of RUNX1 exons 1 and 2 associated with familial platelet disorder with propensity to acute myeloid leukemia

Familial platelet disorder with propensity to acute myeloid leukemia (FPD/AML) associated with RUNX1 mutations is an autosomal dominant disorder included in the group of the myeloid neoplasms with germ line predisposition. We describe two brothers who were diagnosed with hematological malignancies (one with AML and the other with T-cell lymphoblastic lymphoma). There was a history of leukemia in the paternal family and two of their siblings presented with low platelet counts and no history of significant bleeding. A microdeletion encompassing exons 1-2 of RUNX1 (outside the cluster region of the Runt Homology domain and the transactivation domain) was detected in six family members using array-CGH and MLPA validation. A low platelet count was not present in all deletion carriers and, therefore, it should not be used as an indication for screening in suspected families and family members.

Myelodysplastic syndromes in South America: a multinational study of 1080 patients

There are previously reported data describing differences between Asian and European patients with Myelodysplastic Syndromes (MDS), few direct comparisons based on cancer registration characteristics or using cohorts to validate scoring systems. This is the first study from South-America, which attempts to describe demographic, clinical features, and outcome of MDS patients. We retrospectively analyzed 1,080 patients with de novo MDS from Argentina (635), Brazil (345), and Chile (100). Chilean patients were younger (P = 0.001) with female preponderance (P = 0.071). Brazilian series showed a higher predominance of RARS subtype regarding FAB and WHO classifications (P < 0.001). Hemoglobin levels were significantly lower in Brazilian and Chilean series (P < 0.001), and Chilean series also showed a lower platelet count (P = 0.028), with no differences concerning the neutrophil count, % BM blast, and the distribution of cytogenetic risk groups (P > 0.05). Chilean series depicted a lower overall survival (OS; 35 months vs. 56 months-Argentine; 55 months-Brazil, P = 0.030), which was consistent with a higher predominance of the high-risk group according both to the IPSS and IPSS-R (P = 0.046 and P < 0.001). The IPSS-R system and its variables showed a good reproducibility to predict clinical outcome for the whole South-American population. Epidemiological and clinical characteristics, distribution among prognostic subgroups, the OS, and the access to disease modifying therapies were more similar between Argentinean and Brazilian compared with Chilean MDS series. This will need further analysis in a larger group of patients. Descriptive and comparative studies are necessary to establish epidemiological features useful for public health attitudes to generate suitable therapeutic schemes.

Fanconi anemia and vaginal squamous cell carcinoma

Fanconi Anemia (FA) is an autosomal recessive disease characterized by chromosome instability, cellular hypersensitivity to DNA cross-linking agents, and increased predisposition to malignancies. We describe here a 28 year-old female with FA and vaginal squamous cell carcinoma treated by radiation therapy alone. The patient developed arm phlebitis, pulmonary fungal infection, and severe rectal bleeding, followed by hypocalcaemia, hypokalemia, vaginal bacterial and fungal infection, with subsequent leg and arm phlebitis, perineal abscess, and sepsis. The patient died 12 weeks later.