Considerations on diagnosis and surveillance measures of PTEN hamartoma tumor syndrome: clinical and genetic study in a series of Spanish patients

Background

The limited knowledge about the PTEN hamartoma tumor syndrome (PHTS) makes its diagnosis a challenging task. We aimed to define the clinical and genetic characteristics of this syndrome in the Spanish population and to identify new genes potentially associated with the disease.

Results

We reviewed the clinical data collected through a specific questionnaire in a series of 145 Spanish patients with a phenotypic features compatible with PHTS and performed molecular characterization through several approaches including next generation sequencing and whole exome sequencing (WES). Macrocephaly, mucocutaneous lesions, gastrointestinal polyposis and obesity are prevalent phenotypic features in PHTS and help predict the presence of a PTEN germline variant in our population. We also find that PHTS patients are at risk to develop cancer in childhood or adolescence. Furthermore, we observe a high frequency of variants in exon 1 of PTEN, which are associated with renal cancer and overexpression of KLLN and PTEN. Moreover, WES revealed variants in genes like NEDD4 that merit further research.

Conclusions

This study expands previously reported findings in other PHTS population studies and makes new contributions regarding clinical and molecular aspects of PHTS, which are useful for translation to the clinic and for new research lines.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-02079-7.

Macrophages, Metabolism and Heterophagy in the Heart

The heart is a never-stopping engine that relies on a formidable pool of mitochondria to generate energy and propel pumping. Because dying cardiomyocytes cannot be replaced, this high metabolic rate creates the challenge of preserving organelle fitness and cell function for life. Here, we provide an immunologist's perspective on how the heart solves this challenge, which is in part by incorporating macrophages as an integral component of the myocardium. Cardiac macrophages surround cardiomyocytes and capture dysfunctional mitochondria that these cells eject to the milieu, effectively establishing a client cell-support cell interaction. We refer to this heterologous partnership as heterophagy. Notably, this process shares analogies with other biological systems, is essential for proteostasis and metabolic fitness of cardiomyocytes, and unveils a remarkable degree of dependence of the healthy heart on immune cells for everyday function.

Cimp-Positive Status is More Representative in Multiple Colorectal Cancers than in Unique Primary Colorectal Cancers

Colorectal cancer (CRC) with CpG island methylator phenotype (CIMP) is recognized as a subgroup of CRC that shows association with particular genetic defects and patient outcomes. We analyzed CIMP status of 229 individuals with CRC using an eight-marker panel (CACNA1G, CDKN2A, CRABP1, IGF2, MLH1, NEUROG1, RUNX3 and SOCS1); CIMP-(+) tumors were defined as having ≥ 5 methylated markers. Patients were divided into individuals who developed a "unique" CRC, which were subclassified into early-onset CRC (EOCRC) and late-onset CRC (LOCRC), and patients with multiple primary CRCs subclassified into synchronous CRC (SCRC) and metachronous CRC (MCRC). We found 9 (15.2%) CIMP-(+) EOCRC patients related with the proximal colon (p = 0.008), and 19 (26.8%) CIMP-(+) LOCRC patients associated with tumor differentiation (p = 0.045), MSI status (p = 0.021) and BRAF mutation (p = 0.001). Thirty-five (64.8%) SCRC patients had at least one CIMP-(+) tumor and 20 (44.4%) MCRC patients presented their first tumor as CIMP-(+). Thirty-nine (72.2%) SCRC patients showed concordant CIMP status in their simultaneous tumors. The differences in CIMP-(+) frequency between groups may reflect the importance of taking into account several criteria for the development of multiple primary neoplasms. Additionally, the concordance between synchronous tumors suggests CIMP status is generally maintained in SCRC patients.

Clinical and functional characterization of the CDH1 germline variant c.1679C>G in three unrelated families with hereditary diffuse gastric cancer

Germline changes in the CDH1 tumor suppressor gene predispose to diffuse gastric cancer and lobular breast cancer. In carriers of deleterious germline CDH1 variants, prophylactic gastrectomy is recommended. In case of germline missense variants, it is mandatory to assess the functional impact on E-cadherin, the protein encoded by CDH1, and to predict their clinical significance. Herein, we have identified a recurrent germline missense variant, c.1679C>G, segregating with gastric cancer in three unrelated Spanish families. Through genetic, transcriptional, in silico and in vitro studies, we demonstrate the deleterious effect of the c.1679C>G variant and its association with hereditary diffuse gastric cancer, providing relevant data to relatives and allowing an accurate genetic counseling.