awk -v OFS="\t" '/SVTYPE=Fusion/{
                        match($5,/].*]/);
                        sub(/.COS.*/,"",$3);
                        sub(/-/,"",$3);
                        sub(/\./,"-",$3);
                        VAL=substr($5,RSTART+1,RLENGTH-2);
                        num=split($8, array,";");
                        for(i=1;i<=num;i++){
                                                if(array[i] ~  /SVTYPE/){
                                                sub(/.*=/,"",array[i]);
                                                svtype=array[i]
                                                         
               };
                                                if(array[i] ~ /READ_COUNT/){
                                                sub(/.*=/,"",array[i]);
                                                read_count=array[i]
                                                                           }
                                           };
                        match($0,/oncomineGeneClass.*,/);
                        print "Locus\tType\tFunction\tGene\tReads" ### add header
                        print $1":"$2 "-" VAL OFS svtype OFS substr($0,RSTART+20,RLENGTH-22) OFS $3 OFS read_count;
                        ' $8 != "\"SVTYPE=Fusion\"" {print;}'
                    }
' input | awk -F'\t' '!seen[$4]++'### remove duplicates based on $4

awk: cmd. line:21:                         
awk: cmd. line:21:                         ^ unexpected newline or end of string

chr12:12006495-chr15:88483984 Fusion Gain-of-Function ETV6NTRK3-E4N15 1868
chr12:12022903-chr15:88483984 Fusion Gain-of-Function ETV6NTRK3-E5N15 414833

chr12:12006495-chr15:88483984 Fusion Gain-of-Function ETV6NTRK3-E4N15 1868
chr12:12022903-chr15:88483984 Fusion Gain-of-Function ETV6NTRK3-E5N15 414833
chr17 entire line.... (this line does not have the keyword in it so is printed in the output)
chr10 entire line...   (this line does not have the keyword in it so is printed in the output