Association of a novel point mutation in MSH2 gene with familial multiple primary cancers

Background

Multiple primary cancers (MPC) have been identified as two or more cancers without any subordinate relationship that occur either simultaneously or metachronously in the same or different organs of an individual. Lynch syndrome is an autosomal dominant genetic disorder that increases the risk of many types of cancers. Lynch syndrome patients who suffer more than two cancers can also be considered as MPC; patients of this kind provide unique resources to learn how genetic mutation causes MPC in different tissues.

Methods

We performed a whole genome sequencing on blood cells and two tumor samples of a Lynch syndrome patient who was diagnosed with five primary cancers. The mutational landscape of the tumors, including somatic point mutations and copy number alternations, was characterized. We also compared Lynch syndrome with sporadic cancers and proposed a model to illustrate the mutational process by which Lynch syndrome progresses to MPC.

Results

We revealed a novel pathologic mutation on the MSH2 gene (G504 splicing) that associates with Lynch syndrome. Systematical comparison of the mutation landscape revealed that multiple cancers in the proband were evolutionarily independent. Integrative analysis showed that truncating mutations of DNA mismatch repair (MMR) genes were significantly enriched in the patient. A mutation progress model that included germline mutations of MMR genes, double hits of MMR system, mutations in tissue-specific driver genes, and rapid accumulation of additional passenger mutations was proposed to illustrate how MPC occurs in Lynch syndrome patients.

Conclusion

Our findings demonstrate that both germline and somatic alterations are driving forces of carcinogenesis, which may resolve the carcinogenic theory of Lynch syndrome.

Electronic supplementary material

The online version of this article (10.1186/s13045-017-0523-y) contains supplementary material, which is available to authorized users.

Global characteristics of childhood acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) comprises approximately 5-10% of childhood acute myeloid leukemia (AML) cases in the US. While variation in this percentage among other populations was noted previously, global patterns of childhood APL have not been thoroughly characterized. In this comprehensive review of childhood APL, we examined its geographic pattern and the potential contribution of environmental factors to observed variation. In 142 studies (spanning >60 countries) identified, variation was apparent-de novo APL represented from 2% (Switzerland) to >50% (Nicaragua) of childhood AML in different geographic regions. Because a limited number of previous studies addressed specific environmental exposures that potentially underlie childhood APL development, we gathered 28 childhood cases of therapy-related APL, which exemplified associations between prior exposures to chemotherapeutic drugs/radiation and APL diagnosis. Future population-based studies examining childhood APL patterns and the potential association with specific environmental exposures and other risk factors are needed.

Favourable prognostic factors in therapy related acute myeloid leukaemia

INTRODUCTION

Therapy related acute myeloid leukaemia (t-AML) is a distinct clinical entity recognized by the World Health Organization classification occurring after chemotherapy and/or radiation treatment administered for a previous disease. T-AML is characterised by pancytopenia, three-lineage myelodysplasia, high frequency of unfavourable cytogenetics and short survival.

OBJECTIVE

The aim of this study was to analyse clinical, cytogenetic, and cytological characteristics of t-AML and their impact on survival.

METHODS

Seventeen patients with t-AML (8 male and 9 female; median age 59 years) were identified among 730 consecutive patients with acute myeloid leukaemia. The degree of three-lineage dysplasia as well as haematological, cytological and cytogenetic analyses, were assessed by standard methods.

RESULTS

The patients survived a median of 62.5 days with the 10% probability of survival during two years. Prognostically favourable factors were a higher percentage of dysplastic granulocytic cells, age less than 60 years, and presence of prognostically favourable karyotype inv(16), t(15;17), t(8;21).

CONCLUSION

The stated prognostic factors that include age, cytogenetics findings and granulocytic dysplasia analysis could contribute to adequate risk stratification of t-AML, though fuller results would require additional analyses.