The vaccine was approved. In the meanwhile we had been working on the relation between hepatitis B and cancer of the liver. Now, first of all it's kind of logical, you know, if you get chronic infection of the liver the possibility that that would lead to... to cancer is kind of high but there... nobody had ever really been able to study it, you know, because... study it carefully because what are... what are you going to measure, you know? You couldn't identify the virus, you know, so... so getting a relationship was going to be hard.

[Q] Was the epidemiology done already between symptomatic hepatitis and liver cancer?

There was... you see, actually the people who get acute hepatitis very often aren't the ones who go on to get primary cancer of the liver. They can be, you know, they can have periods, but people who get acute hepatitis and recover totally have a much lower probability of getting cancer of the liver than people who become chronically infected. Well, there'd been studies done in Africa by my... who has become my colleague, Professor Payette who was... who was a... the dean of the medical school in... in Dakar in... in Senegal and... and there... there were one or two others who were involved and they... they were, they did pathology and they were able to show that people who subsequently died of primary cancer of the liver — quite common in Senegal — were... had chronic liver disease and it looked like... due to viral chronic so there was that connection, you know, based on... but I was in Oxford again - I'd gone there for a year's sabbatical - and Professor Payette said one of his younger scientists flew over to England and came to see me and he, on behalf of Professor Payette, asked if... if I would collaborate with him on a study of the relation between hepatitis B and primary cancer of the liver in Senegal. Professor Payette had retired from the medical school in Dakar by that time but he was still there quite a lot, quite active, so that started a collaboration we had with a bunch of Senegalese physicians and... and the French, and Tom London went there several times. I was there a few times and we established about a five-, six-year collaboration, which was really pretty good because, you know, they were flitting back and forth to Paris and Senegal and they were coming here and they were in residence. We made some, you know, very good colleagues and friends then. It was... it was kind of exciting.

So we set up a sort of field station in Dakar, and I remember we had a... we had to buy a Land Rover, you know. We had to get the Land Rover from France to Senegal. Then we had to find a place to keep it where nobody would take it, so, you know, I was... I was having a time with the purchasing agency here at Fox Chase trying to figure out, what do you want? A Land Rover? In Senegal? But we... it was... it was a very difficult study to do because they were long range, you know. They take several years but we, and then others, established a very clear relation. But the possibility of this connection had been investigated prior to that by one of... one of our young scientists who worked with us, Bruce Smith, who was with us for several years. And Bruce and I looked at this connection and the... the initial study we did not find a correlation, but in the paper we postulated that the technique we were using was quite insensitive and that if we had earlier cases and more sensitive methods, we predicted that you might find... we gave a... so that was I think the first mention of the association between hepatitis B as measured serologically and cancer and there was subsequently... subsequently substantiated. And that was... and what really got me focused on that was a meeting that I went to in Uganda, in Kampala.