Abstract

The protein composition of ‘negative’ and ‘positive’ cervical scrapes has been compared using electrophoresis to determine whether differences were present that could be used to pre-select specimens with negative cytology. Only one minor difference in the 75–80 kDa region of the silver-stained patterns was detected in extracts from two well-matched groups. Further studies using 2D-electrophoresis and Western blotting identified the major components in this region as two forms of secretory component (SC) and transferrin. Subsequent blotting of 13 extracts from patients with negative smears and 17 extracts from patients with positive smears indicated very significant differences in the expression of the two forms of SC (P < 0.0002), the ‘negatives’ having more of the higher M_r form and the ‘positives’ having more of the lower M_r form. Measuring SC could prove useful for pre-screening cervical scrapes, but more investigations are required to establish the nature of the change and a quantitative method for its detection.