Heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP A2/B1) as a marker of preinvasive lung cancer

One of the most promising approaches to reducing lung cancer mortality is through implementing early detection protocols and developing early intervention strategies. Heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP A2/B1) is an oncofetal protein whose overexpression in epithelial sputum cells can be used as a very early marker to detect lung cancer. Three independent prospective validation trials offer clear examples of the robustness of this technique with sensitivities of about 90%. Recent studies show hnRNP A2/B1 as a marker of field carcinogenesis. Microdissection and posterior analysis of areas immunoreactive to hnRNP A2/B1 demonstrate a clear correlation between overexpression of this ribonucleoprotein and genetic instability. Clonality studies also indicate a common origin for hnRNP A2/B1 immunoreactive premalignant lesions and pulmonary tumors in the same patient. The molecular mechanisms linking hnRNP A2/B1 overexpression and cancer remain to be elucidated, but the use of this molecule as an early marker in the biological history of several tumors has been clearly determined.