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 Table of Contents  
ORIGINAL ARTICLE
Year : 2017  |  Volume : 10  |  Issue : 2  |  Page : 203-207

A cross-sectional study of p53 expression in patients with squamous cell carcinoma cervix: A hospital-based study


Department of Pathology, JN Medical College, KLE University, Belgaum, Karnataka, India

Date of Web Publication30-May-2017

Correspondence Address:
Niharika Singh
Room No. 39, Gangaambika Girls Hostel, JN Medical College, Belgaum - 590 010, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/kleuhsj.ijhs_495_16

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  Abstract 

Context: Cervical cancer is the second most common cancer in women in India and the fourth most common cancer in women worldwide. The p53 is a tumor suppressor gene. Overexpression of p53 is detected by immunohistochemistry (IHC) and it indicates a worsened prognosis in some malignancies.
Aims: The present study was undertaken to assess the expression of p53 by IHC in normal cervical epithelium and squamous cell carcinoma (SCC) cervix. The role of p53 as a potential biomarker by correlating p53 expression with clinico-pathological parameters was also studied.
Settings and Design: Cross-sectional study.
Subjects and Methods: A total of 50 cases of cervical biopsy or hysterectomy specimens of SCC cervix and fifty cases of hysterectomy specimens for other gynecologic causes were included in the study. IHC was used to study the p53 expression in normal and neoplastic cervical epithelium. The p53 positivity was assessed by using a semi quantitative method in SCC cervix. The p53 expression was correlated with various clinico-pathological parameters.
Statistical Analysis Used: Data collected was analyzed using appropriate statistical test.
Results: All the fifty cases (100%) of SCC cervix showed positive p53 expression. The normal cervical epithelium in 90% cases was p53 negative and 10% showed basal layer positivity. A statistically significant correlation was seen between p53 score and menopausal status (P = 0.010).
Conclusions: Overexpression of p53 is suggestive of high grade of tumor.

Keywords: Immunohistochemistry, p53, squamous cell carcinoma cervix


How to cite this article:
Singh N, Bannur H. A cross-sectional study of p53 expression in patients with squamous cell carcinoma cervix: A hospital-based study. Indian J Health Sci Biomed Res 2017;10:203-7

How to cite this URL:
Singh N, Bannur H. A cross-sectional study of p53 expression in patients with squamous cell carcinoma cervix: A hospital-based study. Indian J Health Sci Biomed Res [serial online] 2017 [cited 2022 Sep 29];10:203-7. Available from: https://www.ijournalhs.org/text.asp?2017/10/2/203/207265


  Introduction Top


Cervical cancer is the second most common cancer in women in India, the fourth most common cancer in women worldwide and the most common cause of cancer death in the developing countries.[1],[2],[3]

Over 80% of the cases of the cervical carcinoma present at a fairly advanced stage and in India every year around 122,844 cases of carcinoma cervix are diagnosed with around 67,477 deaths are reported per year due to cervical carcinoma in India.[1],[4] Mortality due to carcinoma cervix is an indicator of health inequities about 86% of all deaths due to carcinoma cervix occur in developing, low- and middle-income countries.[1],[5] For carcinoma cervix, screening has been shown to be an effective method for identifying preneoplastic stage early, thereby reducing the mortality.[4]

The p53 is a tumor suppressor gene located on chromosome 17pl3.1 and by stimulating the transcription of other specific cell cycle control genes it regulates the cell proliferation.[6],[7],[8]

One of the most common genetic alterations in human carcinogenesis is inactivation of wild type p53 gene product.[6],[8],[9] Overexpression of p53 is detected by immunohistochemistry (IHC) and it indicates a worsened prognosis in some malignancies.[10],[11],[12]

This study was undertaken to assess the expression of p53 by IHC in normal cervical epithelium and squamous cell carcinoma (SCC) cervix. The role of p53 as a potential biomarker by correlating p53 expression with clinico-pathological parameters was also studied.


  Subjects and Methods Top


  • Type of study: A cross-sectional study
  • Study period:January 2014–December 2015 (2 years)
  • Sample size: Fifty cases of SCC and fifty normal (age matched)
  • Sample size calculation: 4zα2pq/d2


  • p = 94%; q = 6%; d = 9

  • Study population: All the cases which had been diagnosed as SCC of cervix since January 2014–December 2015 in the Department of Pathology, J.N. Medical College, Belagavi.


The present study was approved by Jawaharlal Nehru Medical College's Institutional Ethics Committee on Human subjects Research (Ref.: MDC/DOME/243).

Clinical data were obtained from the patient's records and requisition forms accompanying the specimens to the department. The specimens were adequately fixed in 10% formalin following which the evaluation of gross features was done.

Then the representative tissue from the hysterectomy specimens were subjected to routine processing for paraffin embedding. For retrospective study, paraffin embedded tissue blocks were retrieved from the archives. Four to five micron thick sections were taken from paraffin embedded blocks, on regular glass slide coated with egg albumin and stained with hematoxylin and eosin stain. The slides were then studied for histopathological features and were graded according to modified Broder's Grade [13],[14] into well differentiated (Grade I), moderately differentiated (Grade II), and poorly differentiated (Grade III) and Wentz and Reagan [15],[16] histological types.

IHC was performed on 2–4 μ thick sections from paraffin embedded block. The sections were taken on commercially available poly-L-lysine coated glass slides. In IHC, antigens were retrieved by heat induced epitope retrieval method using microwave technique (BioGenex EZ-Retriever) with Tris EDTA buffer at pH 9 in. BIOGENEX prediluted monoclonal antibodies to p53 were used for staining and chromogen diamino benzoic acid was used p53 detection.

Nuclear staining either as coarse or fine granular dots will be considered positive.

The intensity of staining and the number or percentage of positive cells will be assessed.

The score of p53 is the sum of intensity and percentage of positive cells (range 0–9) [Table 1].[17] The correlation of this score was done with the clinico-pathological parameters.
Table 1: Intensity of p53 staining pattern

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  Results Top


In the present study, fifty of cases SCC cervix (forty cervical biopsies and ten hysterectomy specimen) were studied from January 2014 to December 2015.

The gross and microscopic features with various clinic-pathological prognostic parameters were studied. Fifty cases of hysterectomy specimens for other gynecological causes were used to study the normal cervical epithelium. All these cases were subjected to IHC for p53 overexpression, the results of which were correlated with various clinic-pathological parameters of carcinoma cervix.

The peak incidence of carcinoma cervix was seen in 5th decade (38%) with a mean age of 49.88. Majority of the patients of carcinoma cervix were of parity 3–5 (64%). Carcinoma cervix was more common in postmenopausal women (60%). Overall white discharge per vaginum (34%) followed by postmenopausal bleeding were the most common clinical presentations in women with carcinoma cervix. Majority of the patients of carcinoma cervix had an exophytic cauliflower-like growth (60%). Among the cases of carcinoma cervix where clinical stage was available, clinical stage IIB was most common. Most of the cases of carcinoma cervix were moderately differentiated (84%). The large cell nonkeratinizing type (60%) of SCC was more common.

Nearly 90% of the cases with normal cervix were negative for p53 expression and rest 10% showed positive p53 expression in basal layer of squamous epithelium [Photomicrograph 1]. All the cases of SCC cervix showed positive p53 expression (100%). The patients in 5th decade showed high p53 score. Although, the correlation between age and p53 score was not statistically significant (P = 0.145). The p53 score was high in patients with high parity; however, no statistically significant association was seen in the present study (P = 0.872). A statistically significant association of p53 score with menopausal status was seen in the present study (P = 0.010). A suggestive significance was seen between the clinical stage and p53 expression. Large cell nonkeratinizing histologic subtype of SCC showed high p53 score in the present study. The Border's Grade II was associated with increased grade (percentage of cells) and with high intensity of p53expression. High p53 score was seen in moderately differentiated (Grade II) SCC, with no statistical significance [Table 2].

Table 2: Broder's Grade distribution of patients studied in relation to p53

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  Discussion Top


The importance of apoptotic pathways in development and progression of cancer is becoming apparent in cancer biology. Cancer cells harboring mutations or genetic damage evade normal apoptotic pathways to prevent their self-destruction.[18],[19]

The tumor suppressor gene p53 induces cell cycle arrest and apoptosis in response to DNA damage. Activation of death gene bax and down regulation of survival genes like bcl-2 is governed by p53 to induce apoptosis.[18],[20]

Normal p53 has a short half-life and is nonimmunodetectable, whereas metabolically stable mutant p53 accumulates in the nucleus of cancer cells. Thus, p53 overexpression is often considered the mutant form which is not able to regulate the cell cycle and apoptosis.[21],[22]

In this study, we studied the p53 expression in fifty cases of SCC cervix and correlated it to the various clinic-pathological variables. In this study, the mean age of patients was 49.88 ± 8.71 years. The peak incidence was seen in the 5th decade. The findings in the present study are similar to the study done by Tan et al.[23] (50.3 years), Tan et al.[24] (51.1 years), Rajaram et al.[25] (52.1 ± 12.46 years), Tjalma et al.[26] (52 years), and Baalbergen et al. (45 years).[27]

This study revealed most of the patients of carcinoma cervix were of parity 3–5. This finding is in concordance with the study done in Delhi [25] (5.23 ± 2.34). However, in the study done in Sweden most of the carcinoma cervix patients were of parity 2.7.[28]

Of the fifty cases of SCC, most of the cases were of large cell nonkeratinizing subtype (60%). This finding is similar to the studies done by Kuniyuki et al. (LCNK - 55.8%) and Bahnassy et al.[29] (LCNK - 60.5%). Vasilescu et al.[30] and Inoue et al.[21] also found similar results. Carcinoma cervix was more frequently observed in postmenopausal women (60%) in our study which was similar to findings of a study done by Madhumati et al.[31]

In our study, most of the carcinoma of cervix were moderately differentiated (84%), similar findings were seen in studies done by Sandhu and Shivakumar et al.[32] (86.2%) and Win et al. (75.9%).[33] However, in the study done by Vasilescu et al., poorly differentiated carcinomas were more commonly seen.[30]

The p53 was expressed in 100% of the cases of carcinoma cervix in our study. Similar positivity pattern has been seen in various studies done by Grace et al.[18] (100%), Baskaran et al.[34] (100%), Nair et al.[35] (100%), Tan et al.[24] (94.4%), and Tjalma et al.[26] (83%). The p53 expression in various studies ranged from 25.2% to 100%.[18],[34],[36],[37],[38],[39],[40],[41],[42] The varying range in different studies may be because of the fixation, antigen retrieval methods, antibody selection, and different scoring system used in various studies having different cut-off levels of positive p53 expression.[36],[39]

In the present study, majority of cases of carcinoma cervix showed moderate intensity of p53 expression (52%) similar to the study done by Grace et al.[18] (69.2%) and Win et al. (37.5%).[33]

Semi quantitative methods was used to co-relate grade of p53 positivity. In our study, about 36% of cases showed p53 positivity in more than 30% of tumor cells. Vasilescu et al.[30] in their study concluded that p53 was a prognostic factor for the aggressiveness of the tumor when more >30% positivity was seen in tumor nuclei. Although studies done by Bahnassy et al.[29] and Tan et al.[23] displayed 57.9% and 65.2% p53 positivity in more than 50% of the tumor cells.

The p53 score was correlated with parity of patients with carcinoma cervix, a high p53 expression was seen in women with high parity. This finding suggests that expression of p53 increased in women with high parity, although not significant (P = 0.872).

High p53 score was seen in postmenopausal women in our study than premenopausal women with carcinoma cervix. This is in concordance with the study done by Madhumati et al.[31] where the p53 overexpression was higher in postmenopausal women (52.6%) as compared to premenopausal women (17.6%). Significant association was found between menopausal status and p53 overexpression in our study (P = 0.010), similar to the study done by Ikuta et al. a significant relation was observed between p53 overexpression and hormonal status (P = 0.01).[43]

Out of the cases where staging was available, a high of p53 score was seen in the later stages of the disease with all three cases of stage IIB showing high score. The difference is of suggestive significance with P = 0.086. These findings were similar to the studies done by Bahnassy et al.[29] and Madhumati et al.,[31] by Ikuta et al.[43] and Grace et al.[18] Ikuta et al. observed that p53 expression was an indicator of unfavorable prognosis in patients of IB1 SCC. It is possible that p53 expression might increase in the more advanced stages of cervical carcinoma due to increased abnormality in control of p53 expression or degradation or an increased incidence of p53 mutation.[43]

While correlating p53 grade with the Broder's grade, in the present study moderately differentiated tumors showed a higher grade. This finding was similar to the study done by Sandhu and Shivakumar [32] and Nair et al.[35] However, in our study, correlation between tumor grade and p53 score was not statistically significant (P = 0.139).


  Conclusions Top


The p53 score increased with the increase in age and parity of the patients; however, the difference was not statistically significant. Similar increase in score of p53 expression was seen with increase in the stage and grade of tumor, but with no statistical significance. The absence of statistical significance may be due to the small sample size of our study.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
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    Tables

  [Table 1], [Table 2]


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