Malignant transformation of mature cystic teratoma to squamous cell carcinoma involves altered expression of p53‐ and p16/Rb‐dependent cell cycle regulator proteins

Ovarian mature cystic teratomas (MCT) uncommonly undergo malignant transformation to squamous cell carcinoma (SCC). While alterations in the p53 tumor suppressor gene and protein have been shown, few studies have analyzed other molecular changes leading to this malignant conversion. The purpose of the present study was to investigate 21 samples of SCC arising in MCT for altered expression in known p53‐ and p16/Rb‐dependent cell cycle regulatory proteins, and the association between their expression and cellular proliferation and histological features. Overexpression of the p53 protein was observed in 14 SCC (67%), while four (19%) had point mutations in the p53 gene. Reduced expression of the p16 protein was observed in 18 SCC (86%), while p16 gene alterations (hypermethylation (29%) and point mutation (33%)) were found in 11 (52%). Furthermore, a statistically significant correlation was observed between p53 and Rb overexpression (P = 0.0010), and the overexpression of both p53 and Rb was respectively significantly correlated with increased cellular proliferation. The results indicate that alterations in both the p53 and p16‐Rb pathways are associated with SCC arising in MCT.     

Comparison of p16(INK4a) expression with p53 alterations in head and neck cancer by tissue microarray analysis

We investigated whether there is a relationship between loss of p16(INK4a) protein expression and p53 alterations in head and neck squamous cell carcinomas (HNSCCs). For this purpose, immunohistochemistry was performed on tissue microarrays of 664 tumours; this represents the largest HNSCC cohort studied for molecular biomarkers. Loss of p16(INK4a) protein expression was associated with aberrant p53 expression (negative or overexpressed) in the total cohort, and with TP53 mutations in 200 tumours analysed (p < 0.0001 each). Both loss of p16(INK4a) expression and p53 alterations differed significantly across both tumour sites and stages, being more prevalent in the hypopharynx than in the other tumour sites and in advanced tumour stages. As a possible link between p53 status and p16(INK4a) loss, we found that increased DNA methyltransferase 1 protein levels occurred preferentially in tumours with aberrant p53 (p = 0.001) and negative p16(INK4a) expression (p = 0.0004). In the total cohort, there was a borderline significant difference in patient survival across three p16(INK4a) expression levels (negative, positive, high), with loss of p16(INK4a) expression showing shortest survival. It is suggested that loss of p16(INK4a) expression and p53 alterations should be viewed as related events involved in the early carcinogenic process.     

Expression of cell cycle-regulatory proteins, MIB-1, p16, p53, and p63, in squamous cell carcinoma of conjunctiva: not associated with human papillomavirus infection

Squamous cell carcinoma (SCC), the most common primary malignant tumor of the conjunctiva, has a variable clinical presentation and immunohistochemical profile. Abundant cell cycles exist, including MIB-1 (Ki67 antigen), p16, p53, and p63, within the conjunctiva SCC. This investigation first reports the expressions of cell cycle markers in SCC. A retrospective study was conducted between December 1976 and June 2004, comprising 13 consecutive patients with conjunctiva SCC who were treated with surgical excision. Detailed clinical parameters were also reviewed. Overexpression of MIB-1, p16, p53, and p63 genes were studied by immunohistochemistry. Genechip containing 39 subtypes was used to elucidate human papillomavirus (HPV). The study group contained 13 (100%) men, with a mean age of 68±18 years and follow-up period of 20±17 months. The sample included four (33%) SCC located in the left eye and two (17%) recurrent SCC. Overexpression of the p53 and p63 was considerably higher than that of the p16 (P<0.01). HPV DNA was not detected in any of the 13 cases. This work first examined the immunohistochemical overexpression of cell cycle (MIB-1, p16, p53, and p63) in SCC. This investigation then showed that the expression of cell cycles in SCC was associated with key tumor clinicopathological features. This approach can help distinguish the potential roles of cell cycle in the development of SCC.     

Immunohistochemical analysis of bcl-2 and p53 expression in breast carcinomas: their correlation with Ki-67 growth fraction

We examined 59 breast cancers for p53 and bcl-2 protein expression by immunohistochemistry. The results were correlated with Ki-67 immunostaining. p53-negativity was noted in 40 cases and the remaining 19 tumours were p53-positive. Thirty-six tumours showed strong expression of bcl-2 and in 23 no staining for this protein was observed. We found statistically significant reverse correlation between expression of p53 and bcl-2 in majority of carcinomas: 31 cases were bcl-2 positive and p53-negative, and 14 tumours were bcl-2-negative and p53-positive. Six carcinomas showed no nuclear staining for Ki-67 and in the remaining 53 the percent of cancer cells positive for Ki-67 ranged from 1 to 60 (mean: 14.6). In these 53 cases we found that bcl-2-positive tumours were characterized by lower proliferation than bcl-2-negative tumours, the mean value of Ki-67 immunostaining being 10.7% and 23.0%, respectively. p53-negative tumours showed lower proliferation than p53-positive tumours: mean Ki-67 index was 10.2% and 23.9%, respectively.We conclude that immunohistochemically detected p53 and bcl-2 proteins show a significant inverse relationship in majority of breast carcinomas and their expression correlates with tumour proliferation (Ki-67 immunostaining).     

Correlation between cathepsin D expression and p53 protein nuclear accumulation in oesophageal squamous cell carcinoma

AIM: The lysosomal protease cathepsin D has been reported to be associated with tumour progression in malignant tumours. Expression of the gene encoding cathepsin D is known to be stimulated by oestrogen in mammary cancer cells. Recent experiments revealed that a p53 DNA binding site is located in the promoter region of the cathepsin D gene. This fact indicates that cathepsin D expression may correlate with p53 protein expression. The purpose of this study is to evaluate the expression patterns of the cathepsin D and p53 proteins in oesophageal squamous cell carcinoma (SCC). METHODS: In 154 patients with oesophageal SCC, expression of the cathepsin D and p53 proteins was measured in tumours by means of immunohistochemistry using monoclonal antibodies against cathepsin D (clone, 1C11) and p53 (clone, BP53-12). RESULTS: Cathepsin D was detected in tumour cells, although it was not found in normal oesophageal epithelium adjacent to carcinoma. High cathepsin D expression (positive tumour cells > 10%) was detected in 76 of 154 cases (49%) and high p53 nuclear expression (positive tumour cells > 50%) was detected in 70 cases (46%). High cathepsin D expression was significantly associated with invasive tumour growth (p = 0.002), poor prognosis (p = 0.049), and nuclear accumulation of p53 protein (p = 0.001). Overexpression of both p53 and cathepsin D was seen in 45 of the 154 cases (29.2%). In addition, there was a positive correlation between the cathepsin D index (percentage of cathepsin D positive tumour cells) and Ki-67 labelling index (percentage of Ki-67 positive tumour cells) in 154 oesophageal SCCs (rho = 0.257; p = 0.009). However, in multivariate survival analysis, cathepsin D expression by the tumours was not an independent prognostic factor in patients with oesophageal SCC (p = 0.236). CONCLUSIONS: The expression of cathepsin D by cancer cells may play an important role in the invasive growth of oesophageal SCC. Overexpression of both p53 and cathepsin D was seen frequently in tumours; p53 gene abnormalities may correlate with cathepsin D overexpression in oesophageal SCC.     

p53 Protein expression in laryngeal squamous cell carcinomas bearing wild-type and mutated p53 gene

We performed an immunohistochemical analysis to investigate the expression of p53 protein in a panel of 18 laryngeal squamous cell carcinomas, 15 primary tumours and three in relapse, previously analysed by us for the presence of p53 gene mutations. Dysplastic and/or normal surrounding mucosa was evaluated in 15 different tumours. The results of our study are the following: (1) expression of p53 protein was observed in one out of five tumours positive for p53 gene mutations (20%) and in 10 out of 13 (80%) negative cases; (2), p53 protein over-expression was frequently observed in normal and/or dysplastic mucosa surrounding either wild-type (7/11) or mutated p53 tumours (2/4); (3), p53 immunoreactive cells showed a pattern of distribution in normal and mildly/moderately dysplastic mucosa (basal layers), different from that in severely dysplastic mucosa (whole thickness). These data further support the hypothesis that p53 protein over-expression may be a marker of the earliest phases of multistep tumorigenesis in laryngeal squamous cell carcinoma.     

Expression of p16 and pRB in invasive breast cancer

We aimed to assess protein expressions of p16 and pRB in breast cancer and explore the clinicopathologic implications. Tissue microarray (TMA) was constructed with 406 cases of breast cancer. The cases were subgrouped into luminal A, luminal B, HER-2, and triple negative breast cancer (TNBC) based on the results of immunohistochemical stains for ER, PR, HER-2, and Ki-67 and fluorescent in situ hybridization (FISH) for HER-2. One hundred and sixty-eight cases were allocated to the subgroup luminal A; 87 cases to the luminal B; 32 cases to the HER-2; and 119 cases to the TNBC. The TNBC group showed the highest negative rate for p16, and the luminal B and HER-2 groups showed the highest positive rate for p16 (P < 0.001). Alteration of p16 was the highest in the luminal B and HER-2 groups, and pRB expression rate was the highest in the HER-2 group and lowest in the luminal A group. In addition, p16(+)/pRB(+) type was the most common in the luminal B group, p16(+)/pRB(-) in the luminal A group, and p16(-)/pRB(+) in the TNBC group (P < 0.001). Altered p16/pRB(+) and non-altered p16/pRB(+) type was the most common in the luminal B, and altered p16/pRB(-) and non-altered p16/pRB(+) type was the most common in the luminal A (P < 0.001). Alteration of p16 was correlated with higher Ki67 labeling index (LI) (P = 0.013), and p16 negativity was correlated with ER negativity (P = 0.002), PR negativity (P = 0.004), and higher Ki67 LI (P < 0.001). pRB positivity was correlated with PR negativity (P = 0.009), HER-2 positivity (P = 0.001), and higher Ki-67 LI (P < 0.001). In luminal group A, p16 alteration was correlated with shorter DFS in univariate analysis (P = 0.024). In conclusion, Expression rates of p16 and pRB differ according to the molecular subgroups of breast cancer and they subsequently correlate with clnicopathologic factors.     

Relation between retinoblastoma and p53 proteins in human papilloma viruses 16/18 positive and negative cancers of the uterine cervix.

AIM: To ascertain the extent of retinoblastoma protein (pRB) expression in comparison to p53 protein and human papilloma viruses (HPV) 16/18 status in cervical carcinomas. METHODS: Fifty cases of invasive cervical carcinoma were HPV typed for genotypes 16 and 18 using consensus primers by polymerase chain reaction (PCR). Immunohistochemistry for pRB and p53 was done on formalin fixed tissue using microwave antigen retrieval and commercially available antibodies. RESULTS: Forty five cases were squamous carcinomas, three were adenocarcinomas, and two were adenosquamous carcinomas. Thirty one cases were HPV 16 positive and one was HPV 18. Sixteen cases showed +4 pRB expression and a further 11 were +3 positive. Seven cases were negative. Only five cases (10%) showed +4 p53 immunostaining, while seven were negative and 15 were +1. Of the 16 pRB +4 positive cases, one was negative for p53 and a further seven were +1 positive. This inverse pattern of staining between pRB and p53 had a p value of < 0.001. No correlation was observed between HPV 16/18 status and p53 and/or pRB staining. CONCLUSIONS: pRB is expressed in the majority of cases of cervical cancer (86%), with more than 75% (+4) of the tumour cell population being positive in 16 cases (32%). There appears to be a general inverse pattern of staining between pRB (high) and p53 (low) in cervical cancer. The expression of both pRB and p53 proteins is independent of the HPV 16/18 status of the tumour.     

The significance of immunohistochemical expression of Ki-67, p53, p21, and p16 in meningiomas tissue arrays

Although histologic grading of meningiomas has prognostic and clinical implications, it is difficult in some cases to predict the outcome of patients. There have been several efforts to evaluate the use of different immunohistochemical markers for predicting meningioma prognosis. We analyzed the immunohistochemical expression of Ki-67, p53, p21, p16, and PTEN proteins in 130 meningiomas (64 benign, 39 atypical, and 27 malignant meningiomas) using tissue microarray. The tumors were graded according to the World Health Organization classification. There was a statistically significant correlation between the expression of Ki-67, p53, p21, p16, and the grade of meningiomas (p0.001). By ordinal logistic regression, p53 and Ki-67 were significantly associated with grade, and an increase of 1% in the labeling index of these markers resulted in an increase in the risk of raising the grade by 2.17 and 1.49, respectively. Histological grade, p53, Ki-67 labeling indices, and overexpression of p16 were strongly associated with decreased event-free survival in univariate analysis. In contrast, multivariate analysis revealed that only tumor grade is an independent factor for predicting meningioma recurrence. We conclude that the Ki-67 and p53 labeling indices are useful additional tools in discriminating atypical from benign or anaplastic meningiomas, especially in histological borderline cases.     

Significance of Ki-67 and p53 immunoexpression in the differential diagnosis of oral necrotizing sialometaplasia and squamous cell carcinoma

Necrotizing sialometaplasia (NS) is a benign condition that usually involves the hard palate and can be mistaken for invasive squamous cell carcinoma (SCC). In this study, we have demonstrated that p53 and Ki-67 staining may assist in the differential diagnosis of NS from SCC. Thirteen cases of NS and 20 cases of oral cavity SCC were randomly selected from our surgical pathology archive from 1992 to 2009. Each case was additionally stained with Ki-67, p53, BCL-2, p16, and epidermal growth factor receptor (EGFR) antibodies. All 13 cases of NS were negatively stained for BCL-2, EGFR, and Ki-67. Three cases (23%) showed weak and focal positive nuclear staining for p53. Two cases (15%) showed positive staining for p16. In 16 well-differentiated SCC cases, p53 was positive in 12 cases (75%); BCL-2, p16, EGFR were positive in 3 cases (18%); and Ki-67 was positive in all cases (100%). In 4 moderately differentiated SCC cases, p53 expression was positive in all cases. Two tumors (50%) had a positive expression of BCL-2. Three cases (75%) had a positive p16 staining, and 1 (25%) had a positive EGFR staining. All cases were positive with high nuclear staining greater than 35% of cells for Ki-67. Ki-67 and p53 showed more intense staining and increased in moderately differentiated SCC comparing with well-differentiated SCC and NS. BCL-2, EGFR, and p16 had the same pattern of staining with the same extent in NS and SCCs. The diagnosis of NS may be difficult and may be supplemented via immunohistochemistry by demonstrating focal or absent p53, low to absent Ki-67 (<10% of cells). Although Ki-67 and p53 staining are generally more intense and are increased in malignancy, these findings may be helpful adjuncts in the differential diagnosis of NS from SCC in appropriate clinical setting.     

Expression of p16 and lack of pRB in primary small cell lung cancer.

The retinoblastoma protein (pRB), p16, and cyclin D1 are major components of the RB pathway, which controls the G1 checkpoint of the cell cycle. Proper regulation of this pathway is crucial for normal cell proliferation. Abnormal forms of these proteins have been found in various types of malignant tumours. In the present report, immunohistochemical techniques were applied to study the expression of pRB, p16, and cyclin D1 in 161 samples of primary small cell lung cancer (SCLC) and 20 samples of non-small cell lung cancer (NSCLC). While pRB and cyclin D1 staining was negative in 161 specimens of SCLC, expression of p16 was observed in 153 samples. In contrast to SCLC, 16 out of 20 NSCLC cases exhibited pRB expression and 15 showed cyclin D1 expression, but only very weak p16 staining was found in five samples. These observations could provide additional criteria for the distinction between SCLC and NSCLC. Furthermore, these findings, based on primary tissues, implicate different mechanisms in the tumourigenesis of SCLC and NSCLC.     

p21WAF1 expression in invasive breast cancer and its association with p53, AP-2, cell proliferation,and prognosis

AIMS: To evaluate the expression and prognostic relevance of p21(WAF1) in breast cancer and to investigate its association with p53, activator protein 2 (AP-2), and cell proliferation (as assessed by Ki-67 expression). METHODS: p21(WAF1) expression was analysed immunohistochemically in a large prospective, consecutive series of 420 patients with breast cancer diagnosed and treated between 1990 and 1995 at Kuopio University Hospital, Kuopio, Finland. Inter-relations between p21(WAF1) expression and p53, AP-2, and Ki-67 were evaluated. The expression of p21(WAF1) was also compared with clinicopathological parameters and the patients' survival. RESULTS: In general, nuclear p21(WAF1) expression was low in carcinomas (median, 2.5%; range, 0-70%). Expression was lowest in lobular carcinomas (chi(2) = 7.4; p = 0.025). p21(WAF1) positive tumours were more often p53 positive (chi(2) = 4.2; p = 0.041) but expression of p21(WAF1) did not correlate with AP-2 expression or Ki-67 in the whole patient group. In addition, the combined expression of p21 and p53 was not associated with AP-2 expression. High nuclear p21(WAF1) positivity (n = 160; 38%) was associated with poor differentiation (chi(2) = 8.1; p = 0.017). In the univariate analyses, p21(WAF1) expression had no prognostic value for predicting breast cancer related survival (BCRS) or recurrence free survival (RFS) in the whole patient group or in the subgroups investigated. However, in postmenopausal patients with lymph node metastases, and oestrogen receptor (ER) and/or progesterone receptor (PR) positive tumours, high p21(WAF1) expression predicted response to adjuvant hormonal treatment with antioestrogens. In the univariate analysis, the significant factors for predicting BCRS were Ki-67 expression, stage, lymph node status, histological grade, ER and PR status, and those for RFS were Ki-67 expression, stage, and lymph node status. In the multivariate analysis, the independent predictors of shorter BCRS were high cell proliferation activity measured by Ki-67 expression (p < 0.001), advanced stage (p < 0.001), and poor differentiation (p = 0.048). Shorter RFS was independently predicted by high cell proliferative activity (p < 0.001) and advanced stage (p < 0.001). CONCLUSIONS: The regulation of p21(WAF1) seems to occur independently of p53 or AP-2 and analysing p21(WAF1) expression provided no prognostic information for patients with breast cancer.     

Expression of cyclin D1, Ki-67 and PCNA in non-small cell lung cancer: prognostic significance and comparison with p53 and bcl-2

Uncontrolled cell proliferation is the hallmark of malignant tumours. Thus, the proliferative potential of tumour cells is an important prognostic factor. However, evaluation of the prognostic significance of the expression of proteins involved in regulation of cell proliferation remains controversial. In the present study, expression of Ki-67, PCNA and cyclin D1 was estimated in a group of 89 surgically resected non-small cell lung carcinomas using immunohistochemistry. The results were compared with expression of bcl-2 and p53 and with clinicopathological parameters including patients' survival. Ki-67 and PCNA were found to be moderately and highly expressed in 39% and 44% of the tumours, respectively. There was a strong correlation between Ki67 and PCNA expression. Forty five of 88 tumours (51%) showed overexpression of cyclin D1. Surprisingly, cyclin D1 was mainly localized in the cytoplasm and only a small group of tumours (9/88, 10%) showed nuclear staining as well. Bcl-2 and p53 expression was observed in 69% and 30% of the tumours, respectively. All these markers were found to be independent of clinicopathological parameters, except for Ki-67 and bcl-2 expression, which was associated with squamous cell carcinomas. It is concluded that none of the markers that were studied can be used as an independent prognostic factor, whereas the following combinations of markers may have favourable prognostic value: p53 positivity and low Ki-67 expression, p53 positivity and lack of cyclin D1 expression, bcl-2 positivity and low Ki-67 expression, and lack of cyclin D1 expression and low Ki-67 expression.     

Validation of tissue microarrays for immunohistochemical profiling of cancer specimens using the example of human fibroblastic tumors

Tissue microarrays allow high-throughput molecular profiling of cancer specimens by immunohistochemistry. Phenotype information of sections from arrayed biopsies on a multitissue block needs to be representative of full sections, as protein expression varies throughout the entire tumor specimen. To validate the use of tissue microarrays for immunophenotyping, we studied a group of 59 fibroblastic tumors with variable protein expression patterns by immunohistochemistry for Ki-67, p53, and the retinoblastoma protein (pRB). Data on full tissue sections were compared to the results of one, two, and three 0.6-mm core biopsies per tumor on a tissue array. Ki-67 and p53 staining was read as two categories (positive or negative). Concordance for this staining between tissue arrays with triplicate cores per tumor and full sections were 96 and 98%, respectively. For pRB staining was read as three categories (high, moderate, or negative), where concordance was 91%. The use of three cores per tumor resulted in lower numbers of lost cases and lower nonconcordance with standard full sections as compared to one or two cores per tumor. Correlations between phenotypes and clinical outcome were not significantly different between full section and array-based analysis. Triplicate 0.6-mm core biopsies sampled on tissue arrays provide a reliable system for high-throughput expression profiling by immunohistochemistry when compared to standard full sections. Triplicate cores offer a higher rate of assessable cases and a lower rate of nonconcordant readings than one or two cores. Concordance of triplicate cores is high (96 to 98%) for two category distinction and decreases with the complexity of the phenotypes being analyzed (91%).     

Alterations in the p16INK4a/cyclin D1/RB pathway in gastrointestinal tract endocrine tumors

A series of 76 cases of gastrointestinal tract endocrine tumors, including 21 poorly differentiated endocrine carcinomas (PDECs, small cell carcinomas) and 55 well-differentiated endocrine neoplasms (WDENs, carcinoids), 18 metastatic and 37 nonmetastatic rectal carcinoids, were examined by immunohistochemical analysis for p16INK4a, cyclin D1, and retinoblastoma protein (pRB) expression. Overexpression of p16INK4a was noted in 16 (76%) of the PDECs and none of the WDENs (P < .0001). Loss of pRB expression was demonstrated in 14 (67%) of the PDECs and 17 (31%) of the WDENs (P = .004). Overexpression of cyclin D1 was noted in 49 (89%) of the WDENs and 3 (14%) of the PDECs (P < .0001). Loss of pRB expression was noted in 11 (61%) of 18 metastatic WDENs and only 6 (16%) of 37 nonmetastatic WDENs (P = .001). The p16INK4a/cyclin D1/pRB pathway was altered in gastrointestinal tract endocrine tumors, and the loss of expression of pRB may be helpful in identifying patients at high risk of metastasis in rectal WDENs.     

Down-regulation of p27Kip1 expression is correlated with increased cell proliferation but not expression of p21waf1 and p53, and human papillomavirus infection in benign and malignant tumours of sinonasal regions

AIMS: Although p27Kip1(p27) is a cyclin-dependent kinase inhibitor and a contribution to tumorigenesis has been hypothesized, the possible role in tumours arising in the nasal and paranasal sinus regions is still unknown. METHODS AND RESULTS: Seventy-six sinonasal tumours, including 28 inverted papillomas (IPs) and 48 squamous cell carcinomas (SCCs), were immunohistochemically investigated, along with 46 exophytic papillomas (EPs) of upper respiratory tract and 34 samples of normal paranasal sinus epithelium. The results were also compared with expression of p21WAF1 (p21) and p53, cell proliferation assessed in terms of Ki67 labelling indices (LIs), and human papillomavirus (HPV) infection. The average p27 scores decreased from normal through to malignant lesions, while Ki67 LI scores showed a stepwise increase, the inverse correlation between scores for all categories being significant (r = - 0.639, P < 0. 0001). In the SCCs, p27 expression was significantly higher in keratinizing than nonkeratinizing type tumours (P < 0.05), while there was no association with p21 and p53 expression. Although HPV DNAs for type 16 and 18 were detected in two (7.4%) of 27 EPs, six (35.8%) of 28 IPs, and nine (28.1%) of 32 SCCs, no relation with p27 scores was evident. CONCLUSION: Loss of p27 expression correlates with increased cell proliferation in sinonasal tumours. Moreover, the expression appears to be associated with keratinization in SCCs of the paranasal sinus. These findings indicate that p27 expression may be a useful marker for the dysregulation of cell kinetics in these tumours.     

肺癌中P63与P53、E-cadherin、Ki-67表达的比较

目的　比较 p6 3及 p5 3、E cadherin(E cad)、Ki 6 7在肺癌中的表达 ,以了解在不同组织类型肺癌发生发展过程中 ,p6 3与抑癌基因 (p5 3)突变、上皮分化标志基因 (E cad)失活及细胞增殖标志基因 (Ki 6 7)激活有无相关性。方法　采用免疫组化S P法分别检测 6 1例原发性肺癌中 p6 3、p5 3、E cad和Ki 6 7的表达情况。 结果　p6 3在肺鳞癌中阳性率为 10 0 0 % ,而在其他组织类型肺癌中 p6 3基本不表达 ,差异有显著性 (P <0 0 5 ) ;在不同分化程度的肺鳞癌中 p6 3、p5 3的表达差异有显著性 (P<0 0 5 ) ,E cad、Ki 6 7的表达差异无显著性 (P >0 0 5 ) ;E cad的表达在小细胞肺癌与肺鳞癌和肺腺癌之间差异有显著性 (P <0 0 5 ) ;Ki 6 7的表达在各种组织类型肺癌之间差异有显著性 (P <0 0 5 ) ;在不同分化程度鳞癌中 p6 3与E cad的表达呈负相关(P <0 0 5 )。结论　p6 3可作为鳞状上皮源性肿瘤标记物 ,是判断鳞状细胞癌的增殖和分化有意义的指标 ,并可作为鉴别分化差的鳞癌和腺癌、小细胞癌的指标。