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Epstein-Barr virus latent membrane protein-1 (LMP-1) 30-bp deletion and Xho I-loss is associated with type III nasopharyngeal carcinoma in Malaysia.

See HS, Yap YY, Yip WK, Seow HF - World J Surg Oncol (2008)

Bottom Line: A significant relationship was found with the Chinese race but not histological type.Coexistence of variants with and without 30-bp deletion was found only in 5/29 plasma samples.Both these variants were not found in non-malignant tissues.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Malaysia. shuishien@yahoo.com

ABSTRACT

Background: Nasopharyngeal carcinoma (NPC) is a human epithelial tumour with high prevalence amongst Chinese in Southern China and South East Asia and is associated with the Epstein-Barr virus (EBV). The viral genome harbours an oncogene, namely, the latent membrane protein 1 (LMP1) gene and known variants such as the 30-bp deletion and loss of XhoI restriction site have been found. Less is known about the relationship between these variants and the population characteristics and histological type.

Methods: In this study, the EBV LMP1 gene variants from 42 NPC and 10 non-malignant archived formalin fixed, paraffin-embedded tissues, as well as plasma from another 35 patients with nasopharyngeal carcinoma were determined by using Polymerase Chain Reaction (PCR). Statistical analysis was performed by using SPSS programme.

Results: LMP1 30-bp deletion was detected in 19/34 (55.9%) of NPC tissues, 7/29 (24.1%) of plasma but absent in non-malignant tissues (8/8). Coexistence of variants with and without 30bp deletion was found only in 5/29 (17.2%) plasma samples but not in NPC tissues. The loss of XhoI restriction site in LMP1 gene was found in 34/39 (87.2%) of the NPC tissues and 11/30 (36.7%) of plasma samples. None of the non-malignant nasopharyngeal tissues (8/8) harbour XhoI-loss variants. LMP1 30-bp deletion was detected in 16/18 Chinese versus 3/15 Malays and 13/16 type III (undifferentiated carcinoma) versus 1/6 type I (keratinizing squamous cell carcinoma). XhoI-loss was found in 19/19 Chinese versus 14/19 Malays and 18/18 type III (undifferentiated) versus 2/5 type I (keratinizing squamous cell carcinoma). Statistical analysis showed that these variants were associated with ethnic race (30-bp deletion, p < 0.05; XhoI-loss, p = 0.046) and histological type of NPC (30-bp deletion, p = 0.011; XhoI-loss, p = 0.006). Nineteen out of 32 NPC tissues (19/32; 59.4%) and 6/24 (25%) of plasma samples showed the coexistence of both the 30-bp deletion and the loss of XhoI restriction site. A significant relationship was found with the Chinese race but not histological type.

Conclusion: The incidence rate of 56% for LMP1 30-bp deletion was lower compared to previously reported rates of 75-100% in NPC tissues. Coexistence of variants with and without 30-bp deletion was found only in 5/29 plasma samples. The incidence rate of XhoI restriction site loss in NPC was comparable to other studies from endemic regions such as Southern China. For the first time, the presence of LMP1 30-bp deletion or XhoI-loss was associated with the Chinese race and type III NPC. Both these variants were not found in non-malignant tissues. The influence of these variants on disease progression and outcome in Chinese and type III NPC requires further investigation.

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Xho I restriction digest analyses of NPC and non-malignant tissues, and plasma samples from NPC patients. M-100-bp DNA ladder marker, B-B95.8 control that with XhoI restriction site (two bands of 67 and 46-bp after XhoI digestion), 1-NPC tissue sample with XhoI restriction site, 2-NPC tissue sample with loss of XhoI site show undigested 113-bp product, 3-Non-malignant nasopharyngeal tissue that retained XhoI restriction site, 4&6-NPC plasma samples with loss of XhoI site show undigested 113-bp product, 5-NPC plasma samples with XhoI restriction site.
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Figure 3: Xho I restriction digest analyses of NPC and non-malignant tissues, and plasma samples from NPC patients. M-100-bp DNA ladder marker, B-B95.8 control that with XhoI restriction site (two bands of 67 and 46-bp after XhoI digestion), 1-NPC tissue sample with XhoI restriction site, 2-NPC tissue sample with loss of XhoI site show undigested 113-bp product, 3-Non-malignant nasopharyngeal tissue that retained XhoI restriction site, 4&6-NPC plasma samples with loss of XhoI site show undigested 113-bp product, 5-NPC plasma samples with XhoI restriction site.

Mentions: As summarized in Table 1, XhoI polymorphic region was successfully amplified in 92.9% (39/42) NPC and 80% (8/10) of non-malignant tissues. PCR with primers X1.1 and X1.2 generates a 113-bp amplicon which harbours the XhoI polymorphic region. If XhoI site is present, restriction enzyme digest of the 113-bp amplicon yields two DNA fragments of 67 and 46-bp. The loss of XhoI restriction site was detected in 87.2% (34/39) of NPC tissues samples (represented in lane 2, Figure 3). All 8 of the amplifiable non-malignant tissues samples retained the XhoI restriction site (represented in lane 3, Figure 3). The loss of XhoI restriction site was statistically higher in the NPC tissues compared to the non-malignant tissues (p < 0.05; Fisher's Exact test). As for the plasma sample, the region spanning the XhoI restriction site in exon 1 was successfully amplified in 85.7% (30/35) of the samples. The loss of XhoI site was found in 11/30 cases (36.7%), (represented in lane 5, Figure 3).


Epstein-Barr virus latent membrane protein-1 (LMP-1) 30-bp deletion and Xho I-loss is associated with type III nasopharyngeal carcinoma in Malaysia.

See HS, Yap YY, Yip WK, Seow HF - World J Surg Oncol (2008)

Xho I restriction digest analyses of NPC and non-malignant tissues, and plasma samples from NPC patients. M-100-bp DNA ladder marker, B-B95.8 control that with XhoI restriction site (two bands of 67 and 46-bp after XhoI digestion), 1-NPC tissue sample with XhoI restriction site, 2-NPC tissue sample with loss of XhoI site show undigested 113-bp product, 3-Non-malignant nasopharyngeal tissue that retained XhoI restriction site, 4&6-NPC plasma samples with loss of XhoI site show undigested 113-bp product, 5-NPC plasma samples with XhoI restriction site.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2265716&req=5

Figure 3: Xho I restriction digest analyses of NPC and non-malignant tissues, and plasma samples from NPC patients. M-100-bp DNA ladder marker, B-B95.8 control that with XhoI restriction site (two bands of 67 and 46-bp after XhoI digestion), 1-NPC tissue sample with XhoI restriction site, 2-NPC tissue sample with loss of XhoI site show undigested 113-bp product, 3-Non-malignant nasopharyngeal tissue that retained XhoI restriction site, 4&6-NPC plasma samples with loss of XhoI site show undigested 113-bp product, 5-NPC plasma samples with XhoI restriction site.
Mentions: As summarized in Table 1, XhoI polymorphic region was successfully amplified in 92.9% (39/42) NPC and 80% (8/10) of non-malignant tissues. PCR with primers X1.1 and X1.2 generates a 113-bp amplicon which harbours the XhoI polymorphic region. If XhoI site is present, restriction enzyme digest of the 113-bp amplicon yields two DNA fragments of 67 and 46-bp. The loss of XhoI restriction site was detected in 87.2% (34/39) of NPC tissues samples (represented in lane 2, Figure 3). All 8 of the amplifiable non-malignant tissues samples retained the XhoI restriction site (represented in lane 3, Figure 3). The loss of XhoI restriction site was statistically higher in the NPC tissues compared to the non-malignant tissues (p < 0.05; Fisher's Exact test). As for the plasma sample, the region spanning the XhoI restriction site in exon 1 was successfully amplified in 85.7% (30/35) of the samples. The loss of XhoI site was found in 11/30 cases (36.7%), (represented in lane 5, Figure 3).

Bottom Line: A significant relationship was found with the Chinese race but not histological type.Coexistence of variants with and without 30-bp deletion was found only in 5/29 plasma samples.Both these variants were not found in non-malignant tissues.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Malaysia. shuishien@yahoo.com

ABSTRACT

Background: Nasopharyngeal carcinoma (NPC) is a human epithelial tumour with high prevalence amongst Chinese in Southern China and South East Asia and is associated with the Epstein-Barr virus (EBV). The viral genome harbours an oncogene, namely, the latent membrane protein 1 (LMP1) gene and known variants such as the 30-bp deletion and loss of XhoI restriction site have been found. Less is known about the relationship between these variants and the population characteristics and histological type.

Methods: In this study, the EBV LMP1 gene variants from 42 NPC and 10 non-malignant archived formalin fixed, paraffin-embedded tissues, as well as plasma from another 35 patients with nasopharyngeal carcinoma were determined by using Polymerase Chain Reaction (PCR). Statistical analysis was performed by using SPSS programme.

Results: LMP1 30-bp deletion was detected in 19/34 (55.9%) of NPC tissues, 7/29 (24.1%) of plasma but absent in non-malignant tissues (8/8). Coexistence of variants with and without 30bp deletion was found only in 5/29 (17.2%) plasma samples but not in NPC tissues. The loss of XhoI restriction site in LMP1 gene was found in 34/39 (87.2%) of the NPC tissues and 11/30 (36.7%) of plasma samples. None of the non-malignant nasopharyngeal tissues (8/8) harbour XhoI-loss variants. LMP1 30-bp deletion was detected in 16/18 Chinese versus 3/15 Malays and 13/16 type III (undifferentiated carcinoma) versus 1/6 type I (keratinizing squamous cell carcinoma). XhoI-loss was found in 19/19 Chinese versus 14/19 Malays and 18/18 type III (undifferentiated) versus 2/5 type I (keratinizing squamous cell carcinoma). Statistical analysis showed that these variants were associated with ethnic race (30-bp deletion, p < 0.05; XhoI-loss, p = 0.046) and histological type of NPC (30-bp deletion, p = 0.011; XhoI-loss, p = 0.006). Nineteen out of 32 NPC tissues (19/32; 59.4%) and 6/24 (25%) of plasma samples showed the coexistence of both the 30-bp deletion and the loss of XhoI restriction site. A significant relationship was found with the Chinese race but not histological type.

Conclusion: The incidence rate of 56% for LMP1 30-bp deletion was lower compared to previously reported rates of 75-100% in NPC tissues. Coexistence of variants with and without 30-bp deletion was found only in 5/29 plasma samples. The incidence rate of XhoI restriction site loss in NPC was comparable to other studies from endemic regions such as Southern China. For the first time, the presence of LMP1 30-bp deletion or XhoI-loss was associated with the Chinese race and type III NPC. Both these variants were not found in non-malignant tissues. The influence of these variants on disease progression and outcome in Chinese and type III NPC requires further investigation.

Show MeSH
Related in: MedlinePlus