in situ hybridization study on PTHrP gene expression in oral carcinoma

本研究的目的是探讨PTHrP基因的表达是否与PTHrP1-34免疫组织化学染色及角化程度有关。本研究采用33例口腔鳞癌患者的活检标本，其中女性11例，男性22例，正常口腔黏膜4例。用免疫组织化学方法(LSAB法)对5μm厚的石蜡切片进行1-34多克隆抗体的免疫组织化学染色和非同位素原位杂交。我们使用地高辛标记的寡核苷酸探针，它是对编码PTHrP6-16氨基酸序列的人PTHrP mRNA的补充。甲状旁腺激素受体基因表达阳性30/33例(91%)。免疫组织化学染色将所有标本分为两组，一组为弱染色，另一组为强染色。虽然强染色组的mRNA阳性信号百分率(100%，13/13)高于弱染色组的85%(17/20)，但通过mRNA的表达很难区分两组。结果提示，PTHrP的转录可能对口腔癌的角化或分化没有太大影响。PTHrP的翻译后加工可能是造成这一现象的主要原因。需要进一步的研究来阐明这个问题。另一个特别关注的是P53和Ki-67的表达以比较PTHrP的表达。P53蛋白在鳞癌组织中表达较多。虽然一些研究人员报道了P53突变与PTHrP在其他一些恶性肿瘤中的关系，但在鳞癌中未发现两者之间有显著的免疫组织化学关系。

The purpose of this study was to determine whether the expression of mRNA of PTHrP is related to the immunohistochemical stains of PTHrP 1 -34 and keratinization. Biopsy specimens from 33 patients, 11 females and 22 males, with oral squamous cell carcinoma and 4 normal mucosal specimens were used for this study. A previously described method of immunohistochemical staining (LSAB method) with polyclonal 1-34 antibodies and non-isotopic in situ hybridization were performed on 5 μm thickness paraffin sections. We used digoxigenin labeled oligonucleotide probe which was complement to the human PTHrP mRNA coding for the amino acid sequence PTHrP 6-16. Positive signals of PTHrP mRNA were present in 30/33 (91 %) specimens. All specimens were classified in two groups, one showed slight stains and another showed intense staining by the immunohistochemical investigation. Although the percentage (100 %, 13/13) of positive signals of the mRNA in the intense stain group is higher than that (85 %, 17/20) in the weak stain group, it was difficult to distinguish two groups by expression of mRNA. The results suggest that transcription of PTHrP might not affect much to keratinization or differentiation of oral cancer. Post translational processing of PTHrP may take a major role for this phenomenon. Additional study is required to elucidate this issue.Another special attention was focused on the expression of p53 and Ki-67 for comparing PTHrP expression. p53 expression was frequently occurred in squamous cell carcinoma specimens. Though some researchers reported that there was a relationship between p53 mutations and PTHrP in some other malignancies, no significant immunohistochemical relationship between those was revealed in squamous cell carcinoma.