Significance of heterogeneous nuclear ribonucleoprotein B1 as a new early detection marker for oral squamous cell carcinoma

The development of an early tumor detection marker for oral cancer is an ob vious need due to the high recurrence rate and poor survival rate. Based on our previous report that overexpression of heterogeneous nuclear ribonucle oprotein (hnRNP) B1 protein was found in 100% of squamous cell carcinomas o f human lung, we applied the same immunohistochemical method, using anti-hn RNP B1 antibody, to human oral squamous cell carcinoma (OSCC), Seven human tissue sections of OSCC showed strong staining with anti-hnRNP B1 antibody, and hnRNP B1 protein of 37 kDa was identified in protein fractions isolate d from six of the cancerous tissue sections, while it was not found in adja cent noncancerous tissue. Moreover, three non-homogeneous (nodular) leukopl akia sections showed significant anti-hnRNP B1 staining. The results sugges t that this antibody detects precancerous lesions as well as advanced lesio ns (stages I to IV) of OSCC, We also present positive results of cytodiagno sis for two smear specimens. All of the above results indicate that hnRNP B 1 is a new and useful marker for early detection of OSCC.