BACKGROUND: Carcinoma cervix is one of the leading causes of cancer deaths and lack of screening is found to be the major risk factor. Hence it is important to use screening methods which have better sensitivity.
OBJECTIVE:
The objective of our current study is to evaluate the diagnostic value of use of immunomarkers like p16INK4a and Ki-67 in cervical smears with HPE as gold standard and to assess their sensitivity and specificity in relation to cervical cytology.
METHODS:
We did immunostaining with p16INK4a and Ki-67 in liquid based cervical cytology sample and cervical biopsy specimens for 30 patients. p16INK4a is expressed in dysplastic cervical cells. Ki-67 is a proliferation marker. In cervical smears (immunocytochemistry), p16INK4a expression was graded as 0-negative, 1-weakly positive and 2-strongly positive. Ki-67 expression was scored according to percentage of dysplastic cells showing nuclear positivity as follows (0-negative, 1-50% of dysplastic cells). In tissue sections (immunohistochemistry), p16 was interpreted as positive or negative and Ki-67 expression was interpreted according to the thickness of epithelium involved.
RESULTS:
p16INK4a showed both nuclear and cytoplasmic staining and was positive in cervical smears of 81.8% of CIN I, 100% of CIN II, CIN III and malignant cases. All cervicitis cases were negative. All the CIN I cases showed weak staining, whereas high grade lesions and malignancy showed strong staining pattern. Ki-67 showed nuclear positivity. 54.5% of CIN I cases showed positivity in 50% of dysplastic cells. These associations were found to be statistically significant. The sensitivity for immunocytochemistry with p16INK4a and Ki-67 was 88.89% and 89.28% respectively, which were more than that for morphological interpretation in cervical cytology (77.78%).
CONCLUSION:
The use of immunomarkers in cervical smears has significantly increased the sensitivity of cervical cancer screening in our study. Hence steps should be taken to incorporate immunocytochemistry in cervical cancer screening in areas with better financial and laboratory resources
