P16INK4A and MIB-1: an immunohistochemical expression in preneoplasia and neoplasia of the cervix.

AIM

To evaluate the potential of p16INK4A and MIB-1 and to compare the expression and interrelationship of these markers in cervical preneoplasias and neoplasias.

MATERIALS AND METHODS

Immunohistochemical analysis of p16 and MIB-1 was performed in n = 63 tissue sections and by matching the corresponding Papanicolaou smears. Staining intensity for p16 was determined using the 0-3 grading system. For MIB-1, labelling indices (LI) were calculated and grading was performed using the I-III scoring system.

RESULTS

No positive staining of p16 was observed in the normal cervical epithelium. With increasing severity of cervical intraepithelial neoplasias (CIN), the p16 expression increased progressively. Significant up-regulation of p16 was observed in carcinoma cervix. MIB-1 LI was observed to increase with increasing grades of CIN, and significant overexpression of MIB-1 was observed in carcinoma cervix. Correlation between grades of p16 and that of MIB-1 among cervical neoplasias showed an increasing p16 expression with consistently increasing MIB-1 LI in the groups of increasing severity.

CONCLUSION

This pattern of overexpression of p16 and MIB-1 demonstrate their use as a diagnostic marker for cervical neoplastic lesion. Therefore, p16 and MIB-1 markers in tissue sections can be used as an adjunct to definitively diagnose preneoplastic and neoplastic lesions in the cervix.