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Luke K S Tan

Publications and source records attributed to Luke K S Tan.

4 recordsLinked to original sources
PubMed2004

The candidate tumor suppressor gene BLU, located at the commonly deleted region 3p21.3, is an E2F-regulated, stress-responsive gene and inactivated by both epigenetic and genetic mechanisms in nasopharyngeal carcinoma.

Loss of heterozygosity at 3p21 is common in various cancers including nasopharyngeal carcinoma (NPC). BLU is one of the candidate tumor suppressor genes (TSGs) in this region. Ectopic expression of BLU results in the inhibition of colony formation of cancer cells, suggesting that BLU is a tumor suppressor. We have identified a functional BLU promoter and found that it can be activated by environmental stresses such as heat shock, and is regulated by E2F. The promoter and first exon are located within a CpG island. BLU is highly expressed in testis and normal upper respiratory tract tissues including nasopharynx. However, in all seven NPC cell lines examined, BLU expression was downregulated and inversely correlated with promoter hypermethylation. Biallelic epigenetic inactivation of BLU was also observed in three cell lines. Hypermethylation was further detected in 19/29 (66%) of primary NPC tumors, but not in normal nasopharyngeal tissues. Treatment of NPC cell lines with 5-aza-2'-deoxycytidine activated BLU expression along with promoter demethylation. Although hypermethylation of RASSF1A, another TSG located immediately downstream of BLU, was detected in 20/27 (74%) of NPC tumors, no correlation between the hypermethylation of these two TSGs was observed (P=0.6334). In addition to methylation, homozygous deletion of BLU was found in 7/29 (24%) of tumors. Therefore, BLU is a stress-responsive gene, being disrupted in 83% (24/29) of NPC tumors by either epigenetic or genetic mechanisms. Our data are consistent with the interpretation that BLU is a TSG for NPC.

Alleles↗
PubMed2003

Modalities of surveillance in treated nasopharyngeal cancer.

OBJECTIVE: We sought to assess the efficacy of different modalities in the detection of disease during the early posttreatment period of nasopharyngeal carcinoma (NPC). Study design and setting We prospectively evaluated 57 patients with NPC who were treated with radiation. A postnasal space (PNS) biopsy, an endoscopic examination, and computed tomography (CT) scans were performed 4 months after treatment. RESULTS: Four patients had evidence of disease in the PNS biopsy specimen. The sensitivity, specificity, and positive and negative predictive values of the endoscopic examination were 75%, 94.3%, 50%, and 98%, respectively, while those of the CT scan were 50%, 49.1%, 6.9%, and 92.9%, respectively. CONCLUSION: In the early postradiation period for patients with NPC, an endoscopic examination is a suitable surveillance modality, but routine CT scanning has no added clinical benefit. SIGNIFICANCE: When an endoscopic examination of the PNS yields normal results, a biopsy is not necessary because the likelihood of disease is low.

Adult↗
PubMed2002

Metachronous adenocarcinoma of the maxillary sinuses: a rare entity.

Malignant tumours of the nasal cavities and paranasal sinuses are uncommon. They constitute less than one per cent of all tumours and less than three per cent of head and neck tumours. Although multiple primary carcinomas of the aerodigestive tract are commonly reported, metachronous maxillary sinus carcinomas are rare. To date, all of these cases reported are of squamous cell origin. The incidence of metachronous maxillary carcinoma involving both sinuses is in the range of 1.4 per cent amongst patients with maxillary carcinoma. We present the first reported case, to our knowledge, of a patient with metachronous adenocarcinoma of the maxillary sinus.

Adenocarcinoma↗