Fig. 1

Detection of BLV provirus in human blood and breast cancer tissue samples by long- fragment PCR. A Schematic presentation of PCR amplification of larger fragment of BLV proviral gene in human samples. The Numbers on the two sides of the double arrow lines indicate the beginning and ending of the fragment amplified by PCR. The number under the double arrow line shows PCR ID and the length of each PCR product. B Determination of long PCR (LP) sensitivity. Positive control (pc) FLK-BLV DNA were diluted to obtain BLV copy numbers of 100, 10, 5 and 1 copy in each PCR reaction. Distilled water was used as negative control (nc). M indicates molecular weight marker (5`LTR and 3`LTR: 100 bp DNA ladder (MIXELL Inc, Hiroshima, Japan); LP-1 ~ LP-6: 1 kb DNA ladder). C Summary of PCR amplification of long-fragments of BLV genome. *The quality of DNA samples extracted from human samples were assessed by PCR amplification of human KRAS gene