P53 loss of heterozygosity (LOH) in formalin-fixed paraffin-embedded leiomyosarcoma (LMS): a novel report

BACKGROUND

The occurrence of p53 loss of heterozygosity (LOH) is a common genetic event in malignancy. LOH occurs when a heterozygous locus loses one of its two parental alleles, becoming homozygous at that locus, by either copy number loss (CNL-LOH) or by becoming copy number neutral (CNN-LOH). A role for CNL-LOH (cnLOH) has been postulated in cancer aetiology. Loss of heterozygosity (LOH) results in irreversible genetic loss.

AIMS

LOH was determined in DNA extracted from formalin-fixed paraffin-embedded (FFPE) leiomyosarcoma (LMS) specimens in a retrospective study from 30 patients, to assess the prognostic significance of LOH. The findings were analysed and their validity assessed. LOH was an adverse prognostic factor in LMS. Prospective uniform standardisation of formalin-fixation techniques is required.

METHODS

DNA was extracted from 169 formalin-fixed paraffin blocks of 30 patients with LMS, following extensive tissue microdissection. Genomic DNA was amplified using the polymerase chain reaction (PCR) technique. Fluorescence-based microsatellite PCR was used to detect and quantitate heterozygosity loss.

RESULTS

LOH was detected at gene locus 17p13 in 16 LMS (Four grade 2 and 12 grade 3 LMS). LOH was not detected in 14 LMS cases (one grade 1, five grade 2 and eight grade 3 LMS). LOH was associated with shorter patient survival.

CONCLUSIONS

The results reported herein endorse the value of utilizing FFPE DNA in identifying LOH as a prognostic factor in LMS. The results have implications for tumour biobanking and precision medicine in patients with sarcomas.

Fatal hypertrophic cardiomyopathy in an infant of a diabetic mother

The case is reported of a male infant with hypertrophic cardiomyopathy (HCM), attributed to maternal diabetes, who, contrary to the usually good prognosis of this condition, died at 11 weeks of age. The clinical, echocardiographic, and pathological findings were indistinguishable from familial HCM, except for the lesser degree of myocardial fiber disarray on microscopic examination.

The microscopic features of inflammatory abdominal aortic aneurysms: discriminant analysis

Up to 15% of abdominal aortic aneurysms are designated as inflammatory. They are characterized by marked fibrous thickening of the aneurysmal wall, with the fibrosis extending into the adjacent retroperitoneum. Thirty-five abdominal aortic aneurysms were studied, 15 inflammatory and 20 atherosclerotic. Of the inflammatory group, 10 were symptomatic and five asymptomatic. For each resection specimen, 59 microscopic features (variables) were scored semi-quantitatively. Discriminant function analysis showed that endarteritis obliterans, fibrosis around nerves or ganglia at the outer margin of mural fibrosis, and the thickness of the combined fibrotic media and adventitia gave a satisfactory high discrimination between atherosclerotic and inflammatory aneurysms. When these three variables are used together, a histological diagnosis of inflammatory aneurysm can be made with an expected accuracy in excess of 80%.

Elastosis in granular cell tumours: prevalence and distribution

Elastosis, a previously unreported feature, was found to be common in granular cell tumours. Twenty-four of 28 consecutive granular cell tumours were shown to display elastosis. The elastosis was found in three main sites: adventitial, interstitial and septal. Elastosis is statistically associated with the fibrosis present within this tumour. It appears that elastic fibres are synthesized by connective tissue cells, possibly induced by the tumour cells.

Rapid progression of tracheal stenosis associated with tracheopathia osteo-chondroplastica

Tracheopathia osteochondroplastica (TPO) is a rare, but increasingly recognised condition in which there is accumulation of calcium phosphate with benign submucous proliferation of cartilage and bone beneath the tracheal mucosa, often with squamous metaplasia of the mucosal columnar epithelium. This condition is usually asymptomatic, but may be slowly progressive, causing haemoptysis, dry cough and dyspnoea. We report a case of TPO in which there was rapid progression of tracheal stenosis such that the size of endotracheal tube that the upper airway would accept changed from 8.00 mm to 3.0 mm during a six-week period. This extreme reduction in airway calibre had not been detected on spirometry nine days prior to his final admission. This is the first report of such rapid progression of tracheal stenosis associated with TPO.

Hereditary haemolytic anaemia due to red cell pyrimidine 5'-nucleotidase deficiency in two Irish families with a note on the benefit of splenectomy

Hereditary haemolytic anaemia with basophilic stippling caused by pyrimidine 5'-nucleotidase deficiency is described in three members of two unrelated Irish families. In one family, the disease was moderately severe and the patient's condition was improved by splenectomy. In the other family the haemolytic anaemia was well compensated. In neither family was there a marked elevation of reduced glutathione. The implications are that pyrimidine 5'-nucleotidase deficiency is a heterogeneous disorder, both clinically and biochemically. In more severe forms splenectomy may be beneficial.