Nasal polyposis in Peutz-Jeghers syndrome: a distinct histopathological and molecular genetic entity

BACKGROUND: Peutz-Jeghers syndrome (PJS) is an autosomal dominant hamartomatous polyposis syndrome of the gastrointestinal tract, caused by a germline STK11/LKB1 mutation. Nasal polyposis was described in the original report by Peutz. Recently, a molecular-genetic association between nasal polyposis and PJS has been reported. OBJECTIVE: To further explore the occurrence and pathogenesis of PJS-related nasal polyposis. METHODS: 51 patients with PJS, 84 unaffected family members and 36 spouses from 18 families with PJS were questioned for the presence of nasal polyposis. 12 PJS-related nasal polyps, 1 carcinoma of the nasal cavity and 28 sporadic nasal polyps were analysed for loss of (wild type) STK11/LKB1, eosinophilia, squamous metaplasia, dysplasia and expression of cyclo-oxygenase 2 and p53. RESULTS: Nasal polyps occurred in 8 of 51 patients with PJS, and were not reported by non-affected family members (p<0.001). Germline STK11/LKB1 mutations were identified in all patients with PJS and nasal polyposis. Loss of heterozygosity was found in four of eight PJS-related nasal polyps, but not in sporadic nasal polyps (p = 0.002). PJS-related nasal polyps showed less eosinophilia than sporadic nasal polyps (p<0.001). Expression of cyclo-oxygenase 2 was found in 11 of 12 PJS-related nasal polyps and 19 of 28 sporadic nasal polyps (p>0.05). Overexpression of p53 was not found. CONCLUSIONS: Nasal polyposis occurs in a significant number of Dutch patients with PJS, one of whom developed a carcinoma in the nasal cavity. The loss of heterozygosity, and the absence of eosinophilia suggest a distinct pathogenesis compared with sporadic nasal polyposis.     

Pyloric gland metaplasia/differentiation in multiple organ systems in a patient with Peutz-Jegher's syndrome

Peutz-Jegher's syndrome (PJS) involves multiple organ systems and the development of hamartomatous, metaplastic, or neoplastic lesions of different cell lineages. Among them, glandular lesions are the most common, but their properties are obscure. We report here a 53-year-old woman with PJS who developed multiple hamartomatous polyps in the jejunum and mucinous glandular lesions in multiple organ systems: glandular metaplasia in the urinary bladder; lobular endocervical glandular hyperplasia in the uterine cervix; mucinous metaplasia in the right fallopian tube; mucinous adenoma in the left ovary. Histological and immunohistochemical analyses disclosed that all of the intestinal and extra-intestinal lesions were associated with pyloric gland metaplasia/differentiation across the organ systems. In the general population, the organs described above rarely or infrequently show pyloric gland phenotype, to say nothing of trans-organ involvement. It is strongly suggested that commitment to pyloric gland metaplasia/differentiation is closely associated with PJS.     

Somatic mutations of the first 14 exons of APC in hamartomatous polyps of the colon

Although hamartomatous or hyperplastic polyps are rarely accompanied by adenomatous or carcinomatous foci, the role of APC (MIM# 175100) mutations in these polyps is not clear. The neoplastic potential of these polyps was assessed with regard to somatic mutation of the first 14 exons of APC. DNA from 14 hamartomatous polyps (12 patients with juvenile polyp, JP; two patients with Peutz‐Jeghers syndrome, PJS) and 27 hyperplastic polyps was used. Exons 1‐14 of APC were amplified using verified oligonucleotide primers, and PCR‐SSCP analysis was performed. Translation‐terminating mutation in exon 15 was also screened using the protein truncation test. All mutations found were transitions or transversions with heterozygous alleles of both wild‐type and mutant APC in exons 2, 9, 10, and 11. Four hamartomatous polyps (three from JP and one from PJS) showed seven, new mutations and one common APC variant (codon 486), whereas no hyperplastic polyps demonstrated mutation. APC mutation was not correlated with previous history of colorectal carcinoma or number of polyps. Since all mutations were missense or silent mutations occurred in exons not previously known to have functionally relevant area, their phenotypic implication appeared to be limited. Hum Mutat 14:351–352, 1999. © 1999 Wiley‐Liss, Inc.     

P-J综合征小肠息肉癌变——附一个家族两代4例病例报道及文献回顾

本文报道一个家族两代4例P-J综合征(Peutz-Jegher′s Syndrome)。母亲于43岁并发十二指肠癌。手术中因癌已与胰腺粘连未能完全切除,术后1月死亡。切除肠段病理检查在息肉与肠癌交界处可见从错构瘤表面腺管垂直延长。至单一粘液性细胞腺瘤性增生、至不典型增生、最终演变为粘液腺癌的逐级过渡图像,支持P-J综合征错构瘤性息肉可以癌变的观点。     

De novo germline mutation in the serine-threonine kinase STK11/LKB1 gene associated with Peutz-Jeghers syndrome

Peutz-Jeghers syndrome (PJS) is an autosomal dominant disease, characterized phenotypically by mucocutaneous pigmentation and hamartomatous polyposis. Affected patients are at an increased risk of developing gastrointestinal and other malignancies. Mutations in the STK11/LKB1 (LKB1) gene, which encodes for a serine-threonine kinase, have been identified as a genetic cause of PJS. Molecular analysis of the LKB1 gene in a simplex case of PJS revealed a substitution of cytosine (C) for guanine (G) at codon 246 in exon 6, resulting in the Tyr246X mutation. The nucleotide substitution leads to a premature stop codon at the 246 residue, predicting a truncated protein and presumed loss of kinase activity. Analysis of DNA from both parents of the PJS patient did not show this mutation, which is therefore a de novo mutation. We isolated DNA from microdissected gastrointestinal hamartomatous polyps in the PJS patient and investigated the loss of heterozygosity (LOH) at the LKB1 locus by real-time fluorescence polymerase chain reaction genotyping using a fluorescent resonance energy transfer technique. The results suggest a different mechanism from LOH in the formation of hamartomatous polyps.     

Peutz-Jeghers syndrome.

Peutz-Jeghers syndrome (PJS, MIM 175,2000) is a disease of autosomal dominant inheritance that is characterised by hamartomatous gastrointestinal polyps and mucocutaneous pigmentation. In addition to problems such as intussusception, PJS predisposes to cancers of several sites. The unusual combination of clinical features makes the identification of the defect underlying PJS particularly interesting. Recently, the PJS gene has been mapped to chromosome 19p13.     

Mutations in the STK11 gene characterize minimal deviation adenocarcinoma of the uterine cervix

Minimal deviation adenocarcinoma (MDA) is a well-differentiated variant of mucinous adenocarcinoma of the uterine cervix and is found relatively infrequently in the general population. However, MDA is strongly associated with Peutz-Jeghers syndrome (PJS), a rare hereditary autosomal disorder characterized by benign hamartomatous polyposis in the gastrointestinal tract and mucocutaneous pigmentation. A serine threonine kinase gene, STK11, has been identified as the tumor suppressor gene responsible for the PJS. In this study we investigated the possible direct role of STK11 in the development of MDA of the uterine cervix. Eleven rare cases of mucinous MDA, not known to be associated with PJS, were screened for the presence of mutations in the STK11 gene by single-strand conformation polymorphism analysis of PCR-amplified DNA fragments. Subsequently our findings were confirmed with cloning and sequencing. As a control, 24 cases of endocervical adenocarcinomas of other histologic subtypes, with no family history of PJS (19 mucinous adenocarcinomas, 4 endometrioid adenocarcinomas, and 1 clear cell adenocarcinoma), 15 cases of squamous cell carcinomas of the uterine cervix, 5 cases of endocervical glands with pyloric gland metaplasia, and 2 deeply situated nabothian cysts were investigated. Somatic mutations of the STK11 gene were confirmed in 6 (55%) of the 11 mucinous MDAs and 1 (5%) of the 19 mucinous adenocarcinomas, but not in the 5 nonmucinous adenocarcinomas, the 15 squamous cell carcinomas, nor the 5 endocervical glands with gastric metaplasia. MDAs with the STK11 mutation had a significantly poorer prognosis than MDAs without the STK11 mutation (p = 0.039). A germline mutation of STK11 was detected in one PJS patient with mucinous adenocarcinoma of the uterine cervix. These results suggest that mutations in the STK11 gene may play an important role in the etiology of MDA of the uterine cervix and may distinguish this rare tumor from other common types of adenocarcinoma of the uterine cervix.     

Osseous metaplasia of the colon in a diversion proctocolitis

Osseous metaplasia within the gastrointestinal tract is a rare phenomenon, seen most frequently in mucinproducing left-sided colonic adenocarcinomas. It has also been documented in a variety of benign conditions, occurring in polyps and lesions associated with inflammation and ulceration. This is the first case report, to the authors' knowledge, of osseous metaplasia associated with a diversion proctocolitis. The diversion was performed following stricture formation, secondary to complicated diverticular disease with diverticular phlegmon formation. In common with other cases, in which osseous metaplasia arises within a background of inflammation, the present case demonstrated stromal fibroblastic proliferation. The underlying pathogenesis of osseous metaplasia has not yet been elucidated, but secretion of various bone morphogenic proteins (belonging to the transforming growth factor-beta superfamily) and increased alkaline phosphatase activity by both epithelial and stromal cells have been documented.     

Peutz-Jeghers syndrome: four novel inactivating germline mutations in the STK11 gene. Mutations in brief no. 227. Online

The diagnosis of Peutz-Jeghers syndrome is based on the occurrence of hamartomatous gastrointestinal polyps and perioral pigment spots. In view of the development of hamartomatous polyps in several syndromes and the variability of pigment spots in Peutz-Jeghers patients, identification of affected individuals is difficult. Recently, germline mutations in the STK11 gene have been reported as a molecular cause of Peutz-Jeghers syndrome. We present four novel inactivating mutations identified by direct sequencing of all 9 exons of the STK11 gene in 4 patients suggestive of Peutz-Jeghers syndrome: three frameshift mutations (125-137del; 474-480del; 516-517insT) and one nonsense mutation (Q220X). Our data obtained in these patients and in those reported previously emphasize the diagnostic value of histological discrimination between different types of hamartomatous polyps and of molecular analysis, particularly in cases with no family history of the disease.     

Allelic imbalance at the LKB1 (STK11) locus in tumours from patients with Peutz-Jeghers' syndrome provides evidence for a hamartoma–(adenoma)–carcinoma sequence

Patients with Peutz-Jeghers' syndrome (PJS) develop hamartomatous gastrointestinal polyps and characteristic pigmentation, as a result of germline mutations in the LKB1 gene. The hamartomas in PJS were long considered to be without malignant potential. There is, however, accumulating epidemiological evidence to suggest that PJS predisposes to cancers at several different sites (colon, pancreas, breast, ovary, testis, and cervix), although large enough patient samples are rarely available to prove this. Allelic imbalance [allele loss, loss of heterozygosity (LOH)] has previously been reported in a small number of PJS polyps, suggesting that LKB1 acts as a tumour suppressor in these tumours. This study confirms allelic loss at LKB1 in PJS polyps and shows that LOH also occurs in cancers of the colon, breast, and cervix in PJS patients. Allele loss was additionally found in a colonic adenoma from a PJS patient, strongly suggesting the existence of a hamartoma–(adenoma)–carcinoma sequence in tumourigenesis. These results provide molecular evidence that PJS patients are predisposed to cancers at several sites, as a direct result of selection for loss of the ‘wild-type’ LKB1 allele in tumours. Given the rare involvement of LKB1 in sporadic cancers, these data also suggest that the indirect effect on cancer risk (or ‘bystander effect’) proposed for hamartomas in juvenile polyposis does not apply to carcinomas in PJS. Copyright © 1999 John Wiley & Sons, Ltd.     

Significance of the smooth muscle cell component in Peutz-Jeghers and juvenile polyps.

We have previously reported the presence of smooth muscle cells (SMCs) in the lamina propria of both tubular and villous adenomatous polyps. In the current study, we investigated the presence and distribution of SMCs with immunohistochemical techniques using anti-alpha smooth muscle actin and anti-desmin antibodies on a series of hamartomatous polyps. In five Peutz-Jeghers polyps, large tree-like branches of SMCs were observed, while in 13 juvenile polyps, rare elongated SMCs were found in the lamina propria, partially surrounding cystically dilated glands. Apart from the quantitative differences, the SMC distribution was similar in the two types of hamartomatous polyps and not dissimilar from the pattern described in neoplastic polyps. These findings make the category "juvenile polyp" less clear and its differentiation from other histologic types of polyp less sharp. Thus, the presence or absence of SMCs cannot form the basis of the differential diagnosis between adenomatous and hamartomatous polyps.     

STK11/LKB1 germline mutations are not identified in most Peutz–Jeghers syndrome patients

Germline mutations of the STK11 gene mapped to chromosome 19p13.3 are responsible for Peutz Jeghers syndrome (PJS), a dominant disorder associated with characteristic gastrointestinal hamartomatous polyps and a predisposition to various cancers. We conducted a detailed investigation of germline STK11 alterations by protein truncation test and genomic DNA sequence analysis in ten unrelated PJS families. We identified a novel truncating deletion spanning STK11 exons 2-7 in a single patient and several known polymorphisms. Loss of heterozygosity studies in PJS polyps of four of these patients identified an allelic deletion of D19S886 in another patient. Our results suggest that STK11 mutations account for only a proportion of PJS cases.     

Molecular genetic alterations in hamartomatous polyps and carcinomas of patients with Peutz-Jeghers syndrome

AIM: To investigate whether mutations in the STK11/LKB1 gene and genes implicated in the colorectal adenoma-carcinoma sequence are involved in Peutz-Jeghers syndrome (PJS) related tumorigenesis. METHODS: Thirty nine polyps and five carcinomas from 17 patients (from 13 families) with PJS were analysed for loss of heterozygosity (LOH) at 19p13.3 (STK11/LKB1 gene locus), 5q21 (APC gene locus), 18q21-22 (Smad4 and Smad2 gene locus), and 17p13 (p53 gene locus), and evaluated for immunohistochemical staining of p53. In addition, mutational analysis of K-ras codon 12, APC, and p53 and immunohistochemistry for Smad4 expression were performed on all carcinomas. RESULTS: LOH at 19p was seen in 15 of the 39 polyps and in all carcinomas (n = 5). Interestingly, six of the seven polyps from patients with cancer had LOH, compared with nine of the 31 polyps from the remaining patients (p = 0.01). In one polyp from a patient without a germline STK11/LKB1 mutation, no LOH at 19p or at three alternative PJS candidate loci (19q, 6p, and 6q) was found. No LOH at 5q was observed. However, mutational analysis revealed an APC mutation in four of the five carcinomas. LOH at 17p was not seen in polyps or carcinomas; immunohistochemistry showed expression of p53 in one carcinoma and focal expression in three polyps. At subsequent sequence analysis, no p53 mutation was found. One carcinoma had an activating K-ras codon 12 mutation and another carcinoma showed 18q LOH; however, no loss of Smad4 expression was seen. CONCLUSIONS: These results provide further evidence that STK11/LKB1 acts as a tumour suppressor gene, and may be involved in the early stages of PJS tumorigenesis. Further research is needed to see whether LOH in PJS polyps could be used as a biomarker to predict cancer. Differences in molecular genetic alterations noted between the adenoma-carcinoma sequence and PJS related tumours suggest the presence of a distinct pathway of carcinogenesis.     

Mutations and impaired function of LKB1 in familial and non-familial Peutz-Jeghers syndrome and a sporadic testicular cancer

Germline mutations in LKB1 have been reported to underlie familial Peutz-Jeghers syndrome (PJS) with intestinal hamartomatous polyps and an elevated risk of various neoplasms. To investigate the prevalence of LKB1 germline mutations in PJS more generally, we studied samples from 33 unrelated PJS patients including eight non-familial sporadic patients, 20 familial patients and five patients with unknown family history. Nineteen germline mutations were identified, 12 (60%) in familial and four (50%) in sporadic cases. LKB1 mutations were not detected in 14 (42%) patients, indicating that the existence of additional minor PJS loci cannot be excluded. LKB1 is predicted to encode a serine/threonine kinase. To demonstrate the putative Lkb1 kinase function and to study the consequences of LKB1 mutations in PJS and sporadic tumors, we have analyzed the kinase activity of wild-type and mutant Lkb1 proteins. Interestingly, while most of the small deletions or missense mutations resulted in loss-of-function alleles, one missense mutation (G163D) previously identified in a sporadic testicular tumor demonstrated severely impaired but detectable kinase activity.      

High proportion of large genomic STK11 deletions in Peutz-Jeghers syndrome

Germline mutations in the STK11 gene have been identified in 10-70% of patients with Peutz-Jeghers syndrome (PJS), an autosomal-dominant hamartomatous polyposis syndrome. A second locus was assumed in a large proportion of PJS patients. To date, STK11 alterations comprise mainly point mutations; only a small number of large deletions have been reported. We performed a mutation analysis for the STK11 gene in 71 patients. Of these, 56 met the clinical criteria for PJS and 12 were presumed to have PJS because of mucocutaneous pigmentation only or bowel problems due to isolated PJS polyps. No clinical information was available for the remaining three patients. By direct sequencing of the coding region of the STK11 gene, we identified point mutations in 37 of 71 patients (52%). We examined the remaining 34 patients by means of the multiplex ligation-dependent probe amplification (MLPA) method, and detected deletions in 17 patients. In four patients the deletion extended over all 10 exons, and in eight patients only the promoter region and exon 1 were deleted. The remaining deletions encompassed exons 2-10 (in two patients), exons 2-3, exons 4-5, or exon 8. When only patients who met the clinical criteria for PJS are considered, the overall mutation detection rate increases to 94% (64% point mutations and 30% large deletions). No mutation was identified in any of the 12 presumed cases. In conclusion, we found that approximately one-third of the patients who met the clinical PJS criteria exhibited large genomic deletions that were readily detectable by MLPA. Screening for point mutations and large deletions by direct sequencing or MLPA, respectively, increased the mutation detection rate in the STK11 gene up to 94%. There may be still other mutations in the STK11 gene that are not detectable by the methods applied here. Therefore, it is questionable whether a second PJS locus exists at all.     

Lipogranuloma with osseous metaplasia in the breast that developed after "Bu-Hwang" oriental medicine treatment

A lipogranuloma is an inflammatory reactive process associated with exogenous or endogenous lipids, and it's occurrence in the breast has rarely been reported. Osseous metaplasia, which is used to describe bone formation in abnormal locations, can develop from several conditions such as trauma or a tumor. However, few studies have reported benign breast lesions that have been seen as osseous metaplasia. We present a case of a benign calcified breast lesion that developed after a traumatic treatment process called "Bu-Hwang", and it was confirmed as a lipogranuloma with osseous metaplasia. To the best of our knowledge, this is the first reported case of a lipogranuloma with osseous metaplasia in the breast.     

Germline and Somatic Mutations of the STK11/LKB1 Peutz-Jeghers Gene in Pancreatic and Biliary Cancers

Peutz-Jeghers syndrome (PJS) is an autosomal-dominant disorder characterized by hamartomatous polyps in the gastrointestinal tract and by pigmented macules of the lips, buccal mucosa, and digits. Less appreciated is the fact that PJS also predisposes patients to an increased risk of gastrointestinal cancer, and pancreatic cancer has been reported in many PJS patients. It was recently shown that germline mutations of the STK11/LKB1 gene are responsible for PJS. We investigated the role of STK11/LKB1 in the development of pancreatic and biliary cancer in patients with and without the PJS. In a PJS patient having a germline splice site mutation in the STK11/LKB1 gene, sequencing analysis of an intestinal polyp and pancreatic cancer from this patient revealed loss of the wild-type allele of the STK11/LKB1 gene in the cancer. Inactivation of STK11/LKB1, by homozygous deletions or somatic sequence mutations coupled with loss of heterozygosity, was also demonstrated in 4-6% of 127 sporadic pancreatic and biliary adenocarcinomas. Our results demonstrate that germline and somatic genetic alterations of the STK11/LKB1 gene may play a causal role in carcinogenesis and that the same gene contributes to the development of both sporadic and familial forms of cancer.     

Phyllodes tumor with a benign heterologous osseous component: a diagnostic challenge

Phyllodes tumors (PTs) are rare fibroepithelial neoplasms of the breast and constitute 0.3–1% of all primary breast tumors. They should be characterized in to a benign, borderline or malignant category based on a combination of histological features. PTs can show heterologous components, typically sarcomatous, including osteosarcomatous and chondrosarcomatous. Benign heterologous components are exceedingly rare with only one prior reported case in the English literature. This case emphasizes how difficult establishing a correct diagnosis in PTs with heterologous components can be, especially when the tumor consists mainly of a benign heterologous component. We report the case of a 65 year old woman with a recurrent breast tumor initially misdiagnosed as benign osseous metaplasia. The tumor re‐occurred as a malignant PT dominated by benign osseous and chondroid metaplasia. Multiple metastases consisting of primarily mature bone and cartilage were seen in the lungs. On microscopic revision and considering the clinical course the primary breast tumor was re‐classified as a borderline PT.     

Oral rapamycin reduces tumour burden and vascularization in Lkb1+/− mice

Patients with Peutz–Jeghers syndrome (PJS) are affected by hamartomatous intestinal polyposis and increased risk of cancers in multiple organs caused by germline mutations in the tumour suppressor gene LKB1. Murine models that recapitulate aspects of PJS have been created. Here we examine the therapeutic effect of rapamycin, a macrolide with anti‐tumourigenic and anti‐angiogenic properties, in reducing tumour incidence in a large cohort of Lkb1^+/? mice. To study the influence of early intervention, the animals were dosed with rapamycin from the age of 8 weeks, well before the onset of polyposis. These mice continued to receive the drug, which was well tolerated, throughout their lives. At sacrifice, we observed a reduction in gastric tumour burden in the rapamycin‐treated mice (p = 0.0001) compared with age‐ and sex‐matched controls. Treated animals also have a lower number of polyps per mouse than controls. In the polyps from the treated mice, phosphorylation of ribosomal p70 S6 kinase was maintained, while the phosphorylation of AKT at serine‐473 was elevated, suggesting that mTORC1 function is maintained at this dosage. Despite this, a significant reduction in microvessel density was seen in polyps from the rapamycin‐treated mice compared to those from the control mice (p = 5 × 10^?5), suggesting that the anti‐angiogenic effect of rapamycin played a role in polyp reduction. Overall, we demonstrated that prolonged oral administration of rapamycin from an early age is effective in lowering tumour burden in the Lkb1^+/? mice without evident side effects. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.