By JOE PLASKO

jplasko@tnonline.comIn detective novels and TV police dramas, those on the side of the law are always looking for the "smoking gun", a reference to a piece of irrefutable evidence that can used to convict the one who perpetrated the crime.In fiction, the smoking gun tends to show up by the end of the story. In reality, such proof can be difficult to find.There were reminders of that during the public forum on polycythemia vera held this week at the Tamaqua Area School District Auditorium.Polycythemia vera (PV) is a rare blood cancer in which the bone marrow makes too many red blood cells, resulting in a thickening of the blood. According to the U.S. Agency for Toxic Substances and Disease Registry (ATSDR), each year, about one in 100,000 people are diagnosed with PV.That makes the cluster of polycythemia vera patients discovered in Schuylkill, Carbon and Luzerne Counties, particularly along Ben Titus Road in Still Creek, north of Tamaqua, alarming.Fortunately, the federal government, through the efforts of Pa. Senator Arlen Specter, himself a cancer survivor, has come up with funding to research the PV cluster.The Tri-County PV Community Action Committee (CAC), a local support group that is working to keep the public informed on the research efforts, sponsored this week's forum. Those in attendance got the chance to talk to those currently performing studies on PV and related myeloproliferative blood diseases (MPDs).It is apparent there is a lot of detective work going on."This is the only situation like this in the country which is getting this level of support for a cancer cluster," said Dr. Vince Seaman of ATSDR.Research is being performed at the University of Pittsburgh, which is following up the original study on the PV cluster; Drexel University, which is doing a case control study to look at potential causes; Mt. Sinai School of Medicine, led by Dr. Ronald Hoffman, which is looking at risk factors, including gene profiling, DNA analysis, and evaluating toxic components; Geisinger Hospital, which is doing a comparative study of 6,000 PV tests in the Danville area; the Pa. Department of Environmental Protection (DEP), which is performing water and soil sampling in the affected region; and ATSDR, which is updating its data warehouse and looking to perform more blood testing for the JAK2 mutation which is present in PV patients.Last year ATSDR tested 1,170 people in the area for JAK2 and came up with 19 positives (1.6 percent), according to Seaman, but 14 of them had the mutation but not the disease.Seaman said there is a risk factor in the DNA for the JAK2 that is hereditary and exists in 40 percent of the population, but it may need some kind of environmental or other stimulus, something in the air or water, to develop."It's a clue to help us look in the right direction," he said.Seaman also noted another study has shown that people in this region live in the same place longer, an average of 24 years, almost three times the national average, which would give them a much longer period to interact with their environment.With the presence of Superfund sites such as McAdoo Associates and cogen plants in the region in proximity to the cluster, it's not a stretch to believe there could be a connection.West Penn Township Physician Dr. Peter Baddick is pressing the issue, and at the forum, he brandished a copy of a U.S Environmental Protection Agency five-year study of the monitoring wells for McAdoo Associations that he claimed displays evidence that chemicals from the site have migrated from the wells over the years.While suspicions abound, the research teams aren't ready yet to claim any smoking guns for PV in the area where we live.