Frequent downregulation of 14-3-3 σ protein and hypermethylation of 14-3-3 σ gene in salivary gland adenoid cystic carcinoma

14-3-3 σ, a target gene of the p53 tumour suppressor protein, has been shown to regulate the cell cycle at the G2/M checkpoint. Recent studies have demonstrated that 14-3-3 σ is downregulated by hypermethylation of the CpG island in several types of cancer. In this study, we investigated the expression and methylation status of 14-3-3 σ in human salivary gland adenoid cystic carcinoma (ACC) and mucoepidermoid carcinoma (MEC). Immunohistochemical analysis revealed that the positive expression rate of 14-3-3 σ in ACC (one out of 14) was markedly lower than that in MEC (ten out of 10). Since most of the ACCs carried the wild-type p53 protein, downregulation of 14-3-3 σ in ACC may not be due to the dysfunction of p53 pathway. Microdissection–methylation-specific PCR revealed that frequent hypermethylation of the 14-3-3 σ gene was observed in ACC when compared to that in MEC. In cultured-ACC cells, we confirmed the downregulation of 14-3-3 σ via hemimethylation of the gene by sequencing analysis after sodium bisulphite treatment. Furthermore, re-expression of 14-3-3 σ in the ACC cells was induced by the treatment with DNA demethylating agent, 5-aza-2′-deoxycytidine. Irradiation apparently induced the enhanced expression of 14-3-3 σ and G2/M arrest in normal salivary gland cells; however, in the ACC cells, neither induction of 14-3-3 σ nor G2/M arrest was induced by irradiation. These results suggest that downregulation of 14-3-3 σ might play critical roles in the neoplastic development and radiosensitivity of ACC

Prognostic value of p27(Kip1 )expression in Basaloid Squamous Cell Carcinoma of the larynx

BACKGROUND: Very few reports have investigated the role of cell cycle regulators as biomarkers in Basaloid Squamous Cell Carcinoma (BSCC) of the larynx, a definite morphologic, uncommon, very aggressive variant of squamous cell carcinoma. Lower expression of Ki67/Mib-1, a proliferation marker highly expressed in the majority of tumours, and p53, a tumour suppressor protein that can induce an arrest of the G1-S transition, was related to a better prognosis in laryngeal BSCC. In the head and neck, p27(kip1), a member of the Cip1/Kip1 family of cyclin-dependent kinase inhibitors, has emerged as an independent prognostic factor, able to identify low-expressing tumours with unfavourable course. Up to date the role of this protein was never studied in BSCC. Aim of our study was to investigate the potential prognostic value of p27(kip1 )levels and their correlation with Ki67/Mib-1 and p53 expression in BSCC of the larynx. METHODS: The retrospective study group consisted of 15 male and 1 female patients, affected by laryngeal BSCC, ranging in age from 44 to 69 years (mean 58). The tumour originated from the supraglottis in thirtheen cases and from the glottis in the remaining three. Ten patients had metastatic cervical lymph nodes at presentation and were classified as N+. Post surgical stage was IV in four patients, III in nine, II in two cases and I in the remaining one. Follow-up ranged from a minimum of 5 months up to 9 years. Paraffin-embedded tissue sections of each laryngeal tumour were analyzed for p27(kip), Ki67/Mib-1 and p53 expression by immunohistochemistry. RESULTS: The immunohistochemical study showed p27(kip1 )expression in 40% of the patients with no evidence of disease (NED) and in none (0%) of the patients dead of disease (DOD), whilst p53 was expressed in 60% of patients in NED status and in 90% of patients in DOD status. Ki67/Mib-1 was positive in 80% of NED patients and in 100% of DOD patients. At multivariate analysis, performed by means of Discriminant analysis, low levels of p27(kip1 )expression significantly correlated with poor prognosis (P < 0.05). CONCLUSION: p27(kip1 )protein has been shown to be a significant independent prognostic factor in laryngeal SCC. In our series of laryngeal BSCC the resulting data seem to confirm the clinical prognostic relevance of p27(kip1 )low expression, which directly correlated with biological aggressiveness and consequent shortened survival

Osteosarcomatous differentiation in lung metastases from a malignant phyllodes tumour of the breast

Osteosarcomatous differentiation of a phyllodes tumour in the breast is extremely rare. A 54 year old woman presented with a painless lump in her left breast and a mastectomy was performed. Microscopically, the tumour was diagnosed as a malignant phyllodes tumour, where no osteosarcomatous component was found. One year later, two lung tumours were revealed upon chest x ray and were surgically treated. The tumours revealed osteosarcomatous features, and were thought to be metastases from the phyllodes tumour. The present case is very unusual in that osteosarcomatous features are present only in the metastatic lesion of the phyllodes tumour