Elsevier

Cancer Genetics

Volume 230, January 2019, Pages 47-57
Cancer Genetics

Original Article
STK11 gene analysis reveals a significant number of splice mutations in Chinese PJS patients

https://doi.org/10.1016/j.cancergen.2018.11.008Get rights and content

Highlights

  • We validated that the combined usage of direct sequencing and MLPA can achieve a high detection rate in Chinese Han PJS patients.

  • We found significantly more splice mutations in Chinese Han PJS patients.

  • We suggest that wide usage of enteroscopy would be helpful in PJS surveillance.

Abstract

Background

The combination of direct sequencing and multiple ligation-dependent probe amplification (MLPA) has resulted in an 80% detection rate of serine/threonine kinase 11 (STK11) gene mutations in Peutz-Jeghers syndrome (PJS); however, this rate varies in different ethnicities.

Aims

To test the efficacy of the combination in Chinese patients with PJS.

Methods

PJS probands visiting our center during one year were enrolled. Sanger sequencing and MLPA were used to detect STK11 mutations. Associations between the occurrence of severe complications and risk factors were analyzed statistically.

Results

We identified 47 PJS probands. Among them, 34 received an STK11 mutation test, revealing 23 point mutations and 2 exonic deletions. Nine of the mutations were splicing errors, reflecting a significantly higher proportion (p < 0.05). Laparotomy history existed for 33 of the probands, and seven families had a history of cancer. Statistical analysis revealed no associations between the occurrence of severe complications or cancers and risk factors.

Conclusion

The strategy achieved a high detection rate in Chinese people, validating its effectiveness. This cohort comprised a significantly higher proportion of splicing errors, reflecting the unique genetic characteristics Chinese people. No specific genotype-phenotype relationship was noted, while the wide usage of enteroscopy would benefit PJS surveillance.

Introduction

Peutz-Jeghers syndrome (PJS; OMIM #175200) is an autosomal dominant inherited disorder, characterized by mucocutaneous pigmentation (MP), hamartomatous polyps of the gastrointestinal (GI) tract (PJPs), and an increased risk of developing of various neoplasms [1], [2]. PJS is also a type of colorectal cancer (CRC syndrome. Family history (FH) is positive in certain cases, whereas others arise de-novo. The incidence of PJS is estimated to be low, at 0.5 to 2 in 100,000 [3]; however, the incidence in a specific country or area is unknown.

As a Mendelian disorder, PJS's genetic cause has been identified as germline mutations in the serine–threonine kinase 11 (STK11) gene [4], [5]. This gene is located on chromosome 19p13.3 and comprises nine exons that encode a 433 amino-acid protein. As a tumor suppressor, STK11 works together with several partners, like STE20-related kinase adaptor alpha (STRADA) and scaffold protein 25 (MO25) [6], and takes part in many biological processes and signaling pathways, such as cell cycle arrest [7], P53-mediated apoptosis [8], Wnt signaling [9], [10], transforming growth factor beta (TGF-β) signaling [11], Ras induced cell transformation [12], and cell polarity [13], [14], [15], [16]. Its extensive participation in biological processes means that functional mutations of STK11 probably cause physiological malfunction in PJS and neoplasms in multiple sites [17].

The diagnosis of PJS consists of two aspects, clinical and genetic. The clinical criteria are taken from the comprehensive system in the Mallorca consensus statement (2007), which allows for any two of the three features (PJP, MP, and FH) or the isolated presence of two or more PJPs to diagnose PJS [3]. The genetic diagnosis is based on the identification of an STK11 germline mutation, although a single study has found an MYH11 (encoding myosin heavy chain 11) germline mutation in a PJS family [18]. The detection methods include Sanger sequencing, next generation sequencing (NGS), denaturing high performance liquid chromatography (DHPLC), single strand conformation polymorphism (SSCP), and multiple ligation-dependent probe amplification (MLPA). Until now, Sanger sequencing plus MLPA, or NGS plus MLPA, have been the best combined detection strategies, with detection rates of 65.8–87.5% [19], [20], [21], [22], [23], [24], [25], [26]. The effectiveness of the combination may vary when applied in different ethnicities. Chinese Han people are one of the most populous races, accounting for more than 20% of the human population; however, data from China are very limited. Previous reports presented PJS detection rates of 67.3% and 81.8%, respectively, using these combinations, which is a marked difference.

In the present study, we applied the combination of direct sequencing and MLPA in a cohort of patients with PJS hospitalized over the course of one year to explore the effectiveness of this strategy in Chinese Han people. We focused on the risk factors that may be associated with the occurrence of polyp-related complications and tumorigenesis.

Section snippets

Subjects

A total of 54 patients were diagnosed clinically with PJS in the Airforce General Hospital of PLA (Beijing) and Changhai Hospital (Shanghai) between Sep 2016 and Aug 2017. The clinical diagnostic criteria of PJS, as recommended by WHO were adopted: (1) Three or more histologically PJPs in the gastrointestinal tract; (2) any number of PJPs detected with a positive FH of PJS; (3) characteristic MP with a positive FH of PJS; and (4) any number of PJPs together with characteristic MP [27]. The

Clinical features

The study process was performed according to the flowchart displayed in Fig. S1. During the whole year investigated (Sep 2016–Aug 2017), 54 patients with clinically diagnosed PJS visited our hospitals and were enrolled in this investigation. The median age of this cohort for diagnosis and first intervention (polypectomy or laparotomy) were 18 and 17 years, respectively, and the proportion of men was 70.4%. Among them, 24 had family history of PJS and 30 did not. Thirty-four patients experienced

Discussion

PJS has various manifestations related to PJPs, such as abdominal pain, distention, hematochezia, chronic anemia, PRP, bowel obstruction, and clinical intussusception [32], [33], [34]. An increased risk of cancer at multiple sites is also a considerable threat to patients with PJS, and the sites range widely, including the GI tract, breast, ovary, testis, and lung [35]. The two main purposes of PJS management/surveillance are to detect sizeable GI polyps and to detect cancer at the early stage

Funding

This work was supported by the National Natural Science Foundation of China [Grant number 81500490]; Application Research of Capital Clinical Character [Grant number Z151100004015215]; the Annual Project of Airforce General Hospital [Grant numbers KZ2015026, KZ2016021]; and the National Key R&D Program of China [Grant number 2017YFC1308800].

Informed consent

Written informed consent was obtained from adult participants and from the legal guardians of child participants in this study.

Conflict of interests

The authors declare that they have no competing interests.

Acknowledgments

We thank the subjects for their participation. We very much appreciate the kind help of Dr. Wen-Sheng Lin and Dr. Hong-Yu Cheng's with the pathological and endoscopic images of the polyps.

References (49)

  • M Tiainen et al.

    Growth suppression by Lkb1 is mediated by a G(1) cell cycle arrest

    Proc Natl Acad Sci USA

    (1999)
  • J Spicer et al.

    Regulation of the Wnt signalling component PAR1A by the Peutz-Jeghers syndrome kinase LKB1

    Oncogene

    (2003)
  • O Ossipova et al.

    LKB1 (XEEK1) regulates Wnt signalling in vertebrate development

    Nat Cell Biol

    (2003)
  • DP Smith et al.

    LIP1, a cytoplasmic protein functionally linked to the Peutz-Jeghers syndrome kinase LKB1

    Hum Mol Genet

    (2001)
  • N Bardeesy et al.

    Loss of the Lkb1 tumour suppressor provokes intestinal polyposis but resistance to transformation

    Nature

    (2002)
  • JL Watts et al.

    The C. elegans par-4 gene encodes a putative serine-threonine kinase required for establishing embryonic asymmetry

    Development

    (2000)
  • SG Martin et al.

    A role for Drosophila LKB1 in anterior-posterior axis formation and epithelial polarity

    Nature

    (2003)
  • N Hearle et al.

    Frequency and spectrum of cancers in the Peutz-Jeghers syndrome

    Clin Cancer Res

    (2006)
  • P Alhopuro et al.

    Unregulated smooth-muscle myosin in human intestinal neoplasia

    Proc Natl Acad Sci USA

    (2008)
  • P Orellana et al.

    Large deletions and splicing-site mutations in the STK11 gene in Peutz-Jeghers Chilean families

    Clin Genet

    (2013)
  • YangHR et al.

    Germline mutation analysis of STK11 gene using direct sequencing and multiplex ligation-dependent probe amplification assay in Korean children with Peutz-Jeghers syndrome

    Dig Dis Sci

    (2010)
  • E Volikos et al.

    LKB1 exonic and whole gene deletions are a common cause of Peutz-Jeghers syndrome

    J Med Genet

    (2006)
  • NC Hearle et al.

    Exonic STK11 deletions are not a rare cause of Peutz-Jeghers syndrome

    J Med Genet

    (2006)
  • ChowE et al.

    An updated mutation spectrum in an Australian series of PJS patients provides further evidence for only one gene locus

    Clin Genet

    (2006)
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    These authors contributed equally to this work.

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