Stathmin (SP49)

The distinction between high grade cervical intraepithelial neoplasia (CIN2/3) from low grade cervical intraepithelial neoplasia (CIN1) is clinically significant with treatment recommendations linked specifically to risk of cancer or CIN3 outcome.1 CIN1 will progress into invasive carcinoma in <1% of cases and is typically managed with papanicolaou smear follow-up, whereas CIN2/3 has a 5% to 20% risk of progression1 and is usually treated with an excisional procedure (loop electrosurgical excision procedure or cone biopsy).1 Stathmin, also referred to as stathmin-1 and oncoprotein18, is a ubiquitous microtubule-destabilizing protein shown to be important during mitosis and has been implicated as a regulator of cell motility and migration.2 Recent studies3 show anti-stathmin is positive in 24/82 (29%) CINs with differential expression based on the grade of the lesion as 5/56 (9%) CIN1, 5/11 (45%) CIN2, and 14/15 (93%) CIN3; whereas, anti-p16 staining of the same cases was immuno-reactive in 66/83 (80%) CINs, including 40/56 (71%) CIN1, 11/11 (100%) CIN2, and 15/16 (94%) CIN3.3 Anti-stathmin shows similar sensitivity for CIN3 to anti-p16 (93% vs 94%) although it drops off for CIN2 (73% vs 96%). The specificity of anti-stathmin for both CIN2/3 (94%) and CIN3 (89%) is higher than that of anti-p16 (44% and 39%, respectively). Anti-stathmin stains basal layer of normal benign ectocervix. A well-oriented fragment of cervix tissue would increase the accuracy of diagnosis. In conclusion, based on recent studies, anti-stathmin has a higher specificity relative to anti-p16; therefore, anti-stathmin has major potential as a diagnostic marker in CIN classification over anti-p16.3