the paper i cited stated 223 protein sequences due to HGT from bacteria.
it also confirms an additional 128, which totals 351.
also, it isn't necessarily quantity that is important, but the value of the gene.
most of the genome, as you know, is composed of junk (or non coding) genes.
the paper outlines 3 important genes that was "inherited" by HGT.
first is hyaluronan synthases (HAS1-3). These were originally proposed as examples of prokaryote-to-metazoan HGT [19], but later rejected [20]; however, neither study considered foreign taxa other than bacteria. We were able to identify all three hyaluronan synthases as class A HGT, originating from fungi, an assessment supported by our phylogenetic analysis (Figure
3). The HAS genes appear in a wide variety of chordates, but not in non-chordate metazoans, suggesting they result from the transfer of a single gene around the time of the common ancestor of Chordata, before undergoing duplications to produce the three genes found in primates.
second is We also identify cases of HGT reported more recently that have not been analysed in detail despite the potentially interesting consequences of such a finding. For example, the fat mass and obesity associated gene (FTO, in Additional file 5: Figure S1A) seems to be present only in marine algae and vertebrates [27,28], which is a highly unusual distribution.
third is Another gene proposed to have been horizontally transferred is the ABO blood group gene (ABO, in Additional file 5: Figure S1B), which is suggested to enhance mutualism between vertebrates and bacteria [29].
as you can see, these are very important genetic transfers that did not happen in the darwinian sense, they did not "evolve".
what's more important is that they became fixed immediately upon acquisition.
so yes, HGT in humans is an important, and proven, fact.