With no explanation, label text_A→text_B with either "not-entailed" or "entailed".
text_A: In the last decade , there has been a real and significant increase in childhood and , to a certain extent , adult carcinoma of the thyroid in contaminated regions of the former Soviet Union ( Wi940 ) which should be attributed to the Chernobyl accident until proven otherwise .
text_B: The proving happened
not-entailed.